scholarly journals Platelet Contractile Proteins

1977 ◽  
Author(s):  
T.D. Pollard
Keyword(s):  
Muscle Contraction ◽  
Outer Surface ◽  
Contractile Force ◽  
Contractile Proteins ◽  
The Body ◽  
High Concentration ◽  
Clot Retraction ◽  
Activated Platelets

Platelets contain a high concentration of the contractile proteins actin and myosin. The properties of these proteins are generally similar to their counterparts in muscle, suggesting that the platelet actin and myosin can generate contractile force. Both proteins are localized in the cytoplasm and little or none of either is present on the outer surface. The distribution of actin in the filopodia and myosin in the body of activated platelets suggests that the force for clot retraction is generated by retraction of the filopodia using a mechanism similar to that in muscle contraction.

Platelet Microtubules in Clot Structure Formation and Contractile Force Generation: Investigation of a Controversy

1986 ◽  
Vol 56 (01) ◽  
pp. 023-027 ◽  
Author(s):  
C J Jen ◽  
L V McIntire
Keyword(s):  
Network Formation ◽  
Contractile Force ◽  
Second Phase ◽  
Clot Retraction ◽  
Forming Process ◽  
Microtubule Organization ◽  
Physiological Processes ◽  
Fibrin Network ◽  
Two Parameters

SummaryWhether platelet microtubules are involved in clot retraction/ contraction has been controversial. To address this question we have simultaneously measured two clotting parameters, clot structural rigidity and isometric contractile force, using a rheological technique. For recalcified PRP clots these two parameters began rising together at about 15 min after CaCl2 addition. In the concentration range affecting microtubule organization in platelets, colchicine, vinca alkaloids and taxol demonstrated insignificant effects on both clotting parameters of a recalcified PRP clot. For PRP clots induced by adding small amounts of exogenous thrombin, the kinetic curves of clot rigidity were biphasic and without a lag time. The first phase corresponded to a platelet-independent network forming process, while the second phase corresponded to a platelet-dependent process. These PRP clots began generating contractile force at the onset of the second phase. For both rigidity and force parameters, only the second phase of clotting kinetics was retarded by microtubule affecting reagents. When PRP samples were clotted by adding a mixture of CaCl2 and thrombin, the second phase clotting was accelerated and became superimposed on the first phase. The inhibitory effects of micro tubule affecting reagents became less pronounced. Thrombin clotting of a two-component system (washed platelets/ purified fibrinogen) was also biphasic, with the second phase being microtubule-dependent. In conclusion, platelet microtubules are important in PRP clotted with low concentrations of thrombin, during which fibrin network formation precedes platelet-fibrin interactions. On the other hand they are unimportant if a PRP clot is induced by recalcification, during which the fibrin network is constructed in the presence of platelet-fibrin interactions. The latter is likely to be more analogous to physiological processes in vivo.

The Toxicity of Castor Beans and its Treatment with Doxycycline in Local Rabbits

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Nael Mohammed Sarheed ◽  
Osamah Faisal Kokas ◽  
Doaa Abd Alabas Muhammed Ridh
Keyword(s):  
Castor Bean ◽  
The Body ◽  
Control Group ◽  
High Concentration ◽  
Biochemical Tests ◽  
Doxycycline Treatment ◽  
High Concentrations ◽  
Physiological Tests ◽  
Animal House ◽  
Physiological And Biochemical

The plant of castor is widely spread in the Iraqi land, and characterized with containing ricin toxin, which has a very serious effects, and because the seeds of this plant scattered in the agricultural soil and rivers water, which increases the exposure of humans and animals to these beans. Objective: This experiment was designed to study the effect of high concentration of castor bean powder in some physiological and biochemical parameters and changes in some tissues of the body, as well as trying to use doxycycline to reduce the effects of ingestion of these seeds. Materials and Methods: In the experiment, 24 local rabbits were raised and fed in the Animal House of the Faculty of Medicine / Al-Muthanna University, then divided into four groups and treated for three weeks (21 days), Control group: treated with normal saline solution (0.9) orally throughout the experiment, G1: was treated orally with a concentration of 25 mg / kg of castor bean powder daily during the experiment, G2 : orally treated 25 mg / kg of castor bean and 25 mg / kg of doxycycline, G3: orally treated 25 mg / kg of castor powder with 50 mg / kg of doxycycline daily throughout the trial period. Results: The results of the experiment showed significant changes (P less than 0.05) in all physiological and biochemical blood tests when compared with control group. There was a significant decrease in PCV, Hb, RBC, T.protein and body weights, while demonstrated a significant increase in WBC, Urea, Creatinine, ALT, AST and ALP, with distortions in liver and kidney of animals that treated with Castor beans. In contrast, the treatment with doxycycline and caster beans showed significant improvement reflected by a normal proportion in physiological tests and biochemical tests with improvement in the tissues when compared to control group. Conclusions: It can be concluded from this study that castor bean has high toxic and pathogenic effects that may be dangerous to the life of the organism. Therefore, it is advisable to be cautious of these pills and avoid exposure to them, also recommended to take high concentrations of doxycycline treatment when infected with castor bean poisoning.

scholarly journals Hypoglycemic and antioxidative activities of ethanol seed extract of Hunteria umbellate (Hallier F.) on streptozotocin-induced diabetic rats

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Olubanke O. Ogunlana ◽  
Babatunde O. Adetuyi ◽  
Miracle Rotimi ◽  
lohor Esalomi ◽  
Alaba Adeyemi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Fasting Blood Glucose ◽  
Diabetic Rats ◽  
Seed Extract ◽  
The Body ◽  
High Concentration ◽  
Group 5

Abstract Background Diabetes, a global cause of mortality in developing countries is a chronic disorder affecting the metabolism of macromolecules and has been attributed to the defective production and action of insulin characterized by persistent hyperglycemic properties. This global disorder harms organs of the body such as the liver, kidney and spleen. Medicinal plants such as Hunteria umbellate have been shown to possess hypoglycemic, antioxidative and anti-diabetic properties owing to the high concentration of active phytochemical constituents like flavonoids and alkaloids. The present study seeks to evaluate the hypoglycemic activities of ethanolic seed extract of Hunteria umbellate on streptozotocin-induced diabetes rats. Methods Thirty (30) female experimental rats were randomly divided into five groups with six rats per group and were administered streptozotocin (STZ) and Hunteria umbellate as follows. Group 1 served as control and was given only distilled water, group 2 rats were administered 60 mg/kg STZ; Group 3 was administered 60 mg/kg STZ and 100 mg/kg metformin; group 4 rats were administered 60 mg/kg STZ and 800 mg/kg Hunteria umbellate, group 5 rats 60 mg/kg STZ and 400 mg/kg Hunteria umbellate. The fasting blood glucose level of each rat was measured before sacrifice. Rats were then sacrificed 24 h after the last dose of treatment. Results The results showed that Hunteria umbellate significantly reversed STZ-induced increase in fasting blood glucose and increase in body and organs weight of rats. Hunteria umbellate significantly reversed STZ-induced decrease in antioxidant enzyme in liver, kidney and spleen of rats. Hunteria umbellate significantly reversed STZ-induced increase in oxidative stress markers in liver, kidney and spleen of rats. Conclusion Collectively, our results provide convincing information that inhibition of oxidative stress and regulation of blood glucose level are major mechanisms through which Hunteria umbellate protects against streptozotocin-induced diabketes rats.

scholarly journals Study of the Soil—Plant (Carrot)—Animal Cycle of Nutritive and Hazardous Minerals in a Rabbit Model

1999 ◽  
Vol 47 (2) ◽  
pp. 181-190 ◽  
Author(s):  
A. Bersényi ◽  
S. Fekete ◽  
I. Hullár ◽  
I. Kádár ◽  
M. Szilágyi ◽  
...  
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Rabbit Model ◽  
Basal Diet ◽  
The Body ◽  
High Concentration ◽  
New Zealand White Rabbits ◽  
Heavy Metal Salts ◽  
Experimental Treatments ◽  
Rate Of Accumulation

Carrots were grown on soils polluted by heavy metal salts. Each particular microelement reached a high concentration [molybdenum (Mo) 39.00, cadmium (Cd) 2.30, lead (Pb) 4.01, mercury (Hg) 30.00, and selenium (Se) 36.20 mg/kg dry matter] in the carrot. In a metabolic balance trial conducted with 15 male and 15 female New Zealand White rabbits, the control animals (n = 5) were fed ad libitum with concentrate as basal diet, while the other rabbits received the basal diet and carrots containing the particular microelement. Blood samples were taken to determine the activity of serum enzymes. To investigate the metabolism of Mo, Cd, Pb, Hg and Se, samples were taken from the heart, liver, lungs, kidneys, spleen, ovaries/testicles, entire digestive tract, adipose tissue, femur, hair, faeces and urine. Carrot had significantly higher digestibility for all nutrients than the rabbit concentrate. Carrot samples of high Pb content had the lowest digestibility of crude protein. The microelements differed in their rate of accumulation in the organs examined: Mo and Cd accumulated in the kidneys, Pb in the kidneys, liver, bones and lungs, Hg in the kidneys and liver, while Se in the liver, kidneys and heart. The proportions of microelements eliminated from the body either via the faeces and urine (Mo 80.18% and Se 47.41%) or via the faeces (Cd 37.86%, Pb 66.39%, Hg 64.65%) were determined. Pathohistological examination revealed that the rate of spermatogenesis was reduced in the Mo, Cd, Pb and Hg groups compared to the control. Lead, Cd and Hg intake resulted in a considerable decrease in gamma-glutamyltransferase (GGT) and in an increase of alkaline phosphatase (ALP) activity because of damages to the kidneys and bones. All experimental treatments decreased the activity of cholinesterase (CHE) because of lesions in the liver.

Ionic regulation and buoyancy in some planktonic organisms

1993 ◽  
Vol 73 (1) ◽  
pp. 15-23 ◽  
Author(s):  
C. Newton ◽  
W. T. W. Potts
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Body ◽  
Coelomic Fluid ◽  
Ionic Regulation ◽  
High Concentration ◽  
Emission Analysis ◽  
X Ray ◽  
Scanning Electron ◽  
Gastrovascular System

Magnesium/chlorine and sulphur/chlorine ratios have been measured in the body fluids of some planktonic organisms by x-ray emission analysis of frozen hydrated specimens in a scanning electron microscope. Homarus vulgaris (Anthropoda: Decapoda) larvae excluded Mg2+ and SO42-ions from the haemolymph, but to a lesser extent than does the adult lobster. Bipinnaria larvae of Asterias (Echinodermata) excluded Mg2+ and SO42-ions from the coelomic fluid. Obelia medusae excluded Mg2+ and SO42-ions from the mesogloea but concentrate them in the gastrovascular system. The high concentration of sulphate in the gastrovascular fluid of medusae has been confirmed by rhodizonate titration in Cyanea and Rhizostoma jellyfish. Some implications of magnesium and sulphate regulation are discussed.

scholarly journals Morphology of lateral line canals in Neotropical freshwater stingrays (Chondrichthyes: Potamotrygonidae) from Negro River, Brazilian Amazon

2010 ◽  
Vol 8 (4) ◽  
pp. 867-876 ◽  
Author(s):  
Akemi Shibuya ◽  
Jansen Zuanon ◽  
Maria Lúcia G. de Araújo ◽  
Sho Tanaka
Keyword(s):  
Lateral Line ◽  
The Body ◽  
Mechanical Stimuli ◽  
High Concentration ◽  
Ventral Region ◽  
Negro River ◽  
Accurate Localization ◽  
Posterior Lateral Line ◽  
The Family ◽  
The Relationship

The relationship between the distribution of the lateral line canals and their functionality has not been well examined in elasmobranchs, especially among Neotropical freshwater stingrays of the family Potamotrygonidae. The spatial distribution of the canals and their tubules and the quantification of the neuromasts were analyzed in preserved specimens of Potamotrygon motoro, P. orbignyi, Potamotrygon sp. "cururu", and Paratrygon aiereba from the middle Negro River, Amazonas, Brazil. The hyomandibular, infraorbital, posterior lateral line, mandibular, nasal and supraorbital canals were characterized and their pores and neuromasts quantified. The ventral canals are known to facilitate the accurate localization of prey items under the body, and our results indicate that the dorsal canals may be employed in identifying the presence of predators or potential prey positioned above the stingray's body. The presence of non-pored canals in the ventral region may be compensated by the high concentration of neuromasts found in the same area, which possibly allow the accurate detection of mechanical stimuli. The concentration of non-pored canals near the mouth indicates their importance in locating and capturing prey buried in the bottom substrate, possibly aided by the presence of vesicles of Savi.

HSP27 in signal transduction and association with contractile proteins in smooth muscle cells

1999 ◽  
Vol 277 (2) ◽  
pp. G445-G454 ◽  
Author(s):  
Adenike I. Ibitayo ◽  
Jeanette Sladick ◽  
Sony Tuteja ◽  
Otto Louis-Jacques ◽  
Hirotaka Yamada ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Smooth Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Smooth Muscle Contraction ◽  
Contractile Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Signal Transduction Cascade ◽  
Kinase C ◽  
Mitogen Activated Protein

Sustained smooth muscle contraction is mediated by protein kinase C (PKC) through a signal transduction cascade leading to contraction. Heat-shock protein 27 (HSP27) appears to be the link between these two major events, i.e., signal transduction and sustained smooth muscle contraction. We have investigated the involvement of HSP27 in signal transduction and HSP27 association with contractile proteins (e.g., actin, myosin, tropomyosin, and caldesmon) resulting in sustained smooth muscle contraction. We have carried out confocal microscopy to investigate the cellular reorganization and colocalization of proteins and immunoprecipitation of HSP27 with actin, myosin, tropomyosin, and caldesmon as detected by sequential immunoblotting. Our results indicate that 1) translocation of Raf-1 to the membrane when stimulated with ceramide is inhibited by vasoactive intestinal peptide (VIP), a relaxant neuropeptide; 2) PKC-α and mitogen-activated protein kinase translocate and colocalize on the membrane in response to ceramide, and PKC-α translocation is inhibited by VIP; 3) HSP27 colocalizes with actin when contraction occurs; and 4) HSP27 immunoprecipitates with actin and with the contractile proteins myosin, tropomyosin, and caldesmon. We propose a model in which HSP27 is involved in sustained smooth muscle contraction and modulates the interaction of actin, myosin, tropomyosin, and caldesmon.

scholarly journals Changes in the thyroid gland during the reproductive cycle of the male vespertilionid bat, Scotophilus heathi

1998 ◽  
Vol 58 (4) ◽  
pp. 707-716 ◽  
Author(s):  
A. KRISHNA ◽  
K. SINGH
Keyword(s):  
Body Weight ◽  
Seasonal Variation ◽  
Thyroid Gland ◽  
Seasonal Change ◽  
Reproductive Cycle ◽  
The Body ◽  
Winter Dormancy ◽  
High Concentration ◽  
Positive Correlation ◽  
Low Concentration

The aim of present study was to compare the changes in thyroid gland with the reproductive cycle of S. heathi. Thyroid showed marked seasonal variation in weight, quantity of colloid and follicular epithelial height, suggesting the thyroid gland to be inactive during quiescence and winter dormancy and active during the time of recrudescence and breeding similarly to the testicular cycle. Plasma thyroxin (T4) concentration showed a significant seasonal change with high concentration during breeding and post-breeding and low concentration during quiescence. However, the T4 concentration increased from breeding to post-breeding phase, when the testes weight was declining. It is suggested that in S. heathi the positive correlation between thyroid and testicular cycles occurs only during the phases of the reproductive cycle when the body weight and testicular activity are also closely correlated.

scholarly journals Dysfunction of muscle contraction with impaired intracellular Ca2+ handling in skeletal muscle and the effect of exercise training in male db/db mice

2019 ◽  
Vol 126 (1) ◽  
pp. 170-182 ◽  
Author(s):  
Hiroaki Eshima ◽  
Yoshifumi Tamura ◽  
Saori Kakehi ◽  
Kyoko Nakamura ◽  
Nagomi Kurebayashi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Muscle Contraction ◽  
Contractile Function ◽  
Contractile Force ◽  
Contractile Dysfunction ◽  
Muscle Contractile ◽  
Type 2 Diabetic

Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.

scholarly journals SOME UNPUBLISHED LANTERNS IN THE ISLAMIC ART MUSEUM IN CAIRO ‬"ANALYTICAL, HISTORICAL AND ARTISTIC STUDY"

2020 ◽  
Vol 2 ◽  
pp. 24-35
Author(s):  
Ghadeer Dardier Afify Khalifa
Keyword(s):  
Outer Surface ◽  
Analytical Study ◽  
Art Museum ◽  
The Body ◽  
Islamic Art ◽  
Large Round ◽  
Metal Frame ◽  
Artistic Styles

This paper aims to study some unpublished lanterns, preserved in the Islamic Art Museum in Cairo through analytical, historical and artistic study. In general, the lanterns are oil lamps and usually with a large round bulbous body, reaching to a narrower center, where above it is the flaming top section. These lanterns can be placed on a surface, however they were commonly suspended by chains and in these chains there were some loops on the outer surface of the body of lanterns that were used to light mosques or any other architectural buildings during Islamic times and in order to light large areas in groups of lanterns, hanging from a metal frame that had the form of a circle, these circular frames continued to be used in many mosques till nowadays. In researching for the collections and antiques, preserved in the Islamic Art Museum in Cairo, it is observed, that there are some unpublished lanterns, have not been discussed and have not been concentrated and strongly investigated by researchers. This study seeks to discuss these unpublished lanterns that include a significant layout of artistic styles, this is besides the historical and archaeological value of these lanterns. The methodology of this study will be addressed through descriptive, historical, artistic and analytical study; this will be revealed through discussion, investigation, analysis that can be detected through detailed interrogation of the objects, elements and structure of the content of this study.

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