Physiological regulation of total tubulin and polymerized tubulin in tissues.

Polymerized and depolymerized forms of tubulin were measured in rat and mouse liver, rat islets, human lymphocytes, and platelets. The percent of the total tubulin present in the polymerized form varied from 30.3 +/- 1.5% in the liver of the fed rat to 89.2 +/- 0.2% in human platelets. Fasting decreased the total tubulin and to a greater extent the polymerized form of tubulin in both rat and mouse liver. Glucose feeding increased the polymerized tubulin without affecting the total tubulin content in rat liver. Phytohemagglutinin-stimulated lymphocytes exhibited at least a three-fold increase in total tubulin (expressed in terms of DNA content), which during the initial 48 h of incubation was accounted for in toto by an increase in polymerized tubulin. It is suggested that the lectin not only accelerates tubulin synthesis but also stimulated the polymerization process. Storage of platelets at 4 degrees C for 6 days resulted in a marked decrease in total tubulin and an even greater reduction in the polymerized form. It is concluded that both the total tubulin content and its degree of polymerization can be modulated independently by a wide variety of physiological factors.

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Increased Protein Synthesis by Human Platelets during Phagocytosis of Latex Particles in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647928 ◽

1976 ◽

Vol 35 (02) ◽

pp. 350-357 ◽

Cited By ~ 8

Author(s):

Hana Bessler ◽

Galila Agam ◽

Meir Djaldetti

Keyword(s):

Protein Synthesis ◽

Fold Increase ◽

Human Platelets ◽

Polystyrene Latex ◽

Latex Particles ◽

The Third ◽

Platelet Protein ◽

Dose Dependent ◽

Phagocytotic Activity

SummaryA three-fold increase of protein synthesis by human platelets during in vitro phagocytosis of polystyrene latex particles was detected. During the first two hours of incubation, the percentage of phagocytizing platelets and the number of latex particles per platelet increased; by the end of the third hour, the first parameter remained stable, while the number of latex particles per cell had decreased.Vincristine (20 μg/ml of cell suspension) inhibited platelet protein synthesis. This effect was both time- and dose-dependent. The drug also caused a decrease in the number of phagocytizing cells, as well as in their phagocytotic activity.

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Diadenosine 5',5'''-p1,p4-tetraphosphate deficiency in blood platelets of the Chediak-Higashi syndrome

Blood ◽

10.1182/blood.v66.3.735.735 ◽

1985 ◽

Vol 66 (3) ◽

pp. 735-737 ◽

Cited By ~ 12

Author(s):

BK Kim ◽

FC Chao ◽

R Leavitt ◽

AS Fauci ◽

KM Meyers ◽

...

Keyword(s):

Whole Blood ◽

Marked Decrease ◽

Blood Platelets ◽

Human Platelets ◽

Dense Granule ◽

Atp Level ◽

Dense Granules ◽

Moderate Reduction ◽

Normal Human ◽

Chediak Higashi Syndrome

Abstract Diadenosine tetraphosphate (AP4A) is an unusual nucleotide found in a variety of cells, including platelets. It has been suggested that platelet AP4A is stored in the dense granules and is metabolically inactive. We have studied the AP4A content of blood platelets in two patients and three cattle with Chediak-Higashi syndrome (CHS), a hereditary platelet defect with dense granule deficiency. Acid-soluble extractions of whole blood and platelets were neutralized. The adenosine triphosphate (ATP) level was measured by luminescence technique. To measure the AP4A content, the neutralized extract was treated with phosphomonoesterase for removal of ATP. The AP4A content was then measured by coupling the phosphodiesterase and luciferase reaction. The AP4A content was 0.43 nmol/mg protein for normal human platelets and 0.004 nmol/mg protein for CHS platelets. The ATP/AP4A ratio was 67 for normal and 3,023 for CHS platelets. The whole blood AP4A was reduced by 89% in CHS patients who had only a slight decrease in ATP level (26% reduction). Similarly, bovine platelets with CHS showed a marked decrease of AP4A content and a moderate reduction of the ATP level. The platelet ATP/AP4A ratio was 351 and 3,133 for normal and CHS cattle, respectively. Results demonstrate a marked reduction of AP4A in CHS platelets and suggest that AP4A may be a useful marker for the measurement of dense granule content in platelets.

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Creatine kinase expression and creatine phosphate accumulation are developmentally regulated during differentiation of mouse and human monocytes.

Journal of Experimental Medicine ◽

10.1084/jem.159.3.746 ◽

1984 ◽

Vol 159 (3) ◽

pp. 746-757 ◽

Cited By ~ 20

Author(s):

J D Loike ◽

V F Kozler ◽

S C Silverstein

Keyword(s):

Creatine Kinase ◽

Human Lymphocytes ◽

Creatine Phosphate ◽

Human Platelets ◽

In Vitro Cultivation ◽

Human Monocytes ◽

Blood Monocytes ◽

Developmentally Regulated ◽

The Brain

We have studied the expression of creatine kinase (CK) and the accumulation of creatine phosphate during the differentiation of human and mouse peripheral blood monocytes. Mouse monocytes cultured for 24 h do not contain detectable levels of CK and creatine phosphate. However, resident tissue macrophages and inflammatory elicited macrophages obtained from the peritoneal cavities of mice have 70 and 300 mU per mg protein of CK activity and contain 3 and 6 mol of creatine phosphate per mol of ATP, respectively. The major isozyme of CK in these cells has been identified as the brain form. These findings suggest that the differentiation of monocytes into macrophages is associated with the expression of CK and the accumulation of creatine phosphate. We have found a similar pattern in human monocytes. Human blood monocytes, maintained in culture for 24 or 48 h, do not contain detectable levels of CK or creatine phosphate. Monocyte-derived macrophages (monocytes maintained in tissue cultures for 1 to 2 wk) have up to 100 mU per mg protein of CK activity and contain 0.5 mol of creatine phosphate per mol of ATP. Human macrophages express multiple isozymes of CK including the brain (BB) and possibly the mitochondrial forms of this enzyme. Thus, the expression of CK and the accumulation of creatine phosphate in human monocytes is induced by their in vitro cultivation. The induction of CK during in vitro cultivation occurs independently of the concentration of creatine in the medium. However, the size of the creatine phosphate pool varies with respect to extracellular creatine concentration. Creatine phosphate and CK are not detectable in freshly isolated human lymphocytes, polymorphonuclear leukocytes or erythrocytes, but are found in freshly isolated human platelets.

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Electron Microscope Analysis of the Surface Charge of Human Platelets; Stored and Aggregated by Polymeric Bases

10.1055/s-0039-1689362 ◽

1975 ◽

Author(s):

Y. Taketomi ◽

A. Ihara ◽

A. Kuramoto ◽

H. Uchino

Keyword(s):

Molecular Weight ◽

Sialic Acid ◽

Plasma Membranes ◽

Particle Density ◽

Average Distance ◽

Human Platelets ◽

Degree Of Polymerization ◽

Surface Coat ◽

Cationic Polymers ◽

Neuraminidase Treatment

The stainability of the surface coat of human platelets with positively charged colloidal Thorotrast was studied on the stored and aggregated platelets by some aggregating agents. During storage, the total sialic acid decreased and fell to 65% of initial value on 5th day. The sialic acid released from fresh platelets by neuraminidase treatment was 80% of the total. The density of Thorotrast particles on surface coat did not change during storage up to 7 days. These particles were abolished to some extent from the surface of neuraminidase treated platelets. These particle density did not change significantly in ADP and collagen induced aggregates but decreased in aggregates induced by cationic polymers such as protamine sulfate and polylysine. At the same concentration of polylysines of different degree of polymerization, maximal aggregation was greater with the higher molecular weight. Average distance between the plasma membranes of two adjacent cells in the aggregate was rather wider when the higher molecular weight polylysine was used.

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Physiological factors affecting secretion of parotid hormone

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1987.252.4.e477 ◽

1987 ◽

Vol 252 (4) ◽

pp. E477-E484 ◽

Cited By ~ 3

Author(s):

J. Leonora ◽

J. M. Tieche ◽

J. Celestin

Keyword(s):

Parotid Gland ◽

Fluid Transport ◽

Fold Increase ◽

Physiological Process ◽

Tissue Extract ◽

Control Mechanisms ◽

Physiological Factors ◽

Factors Affecting ◽

Oral Microbes ◽

Endocrine Axis

A parotid hormone (PH) that stimulates a dentinal fluid transport (DFT) mechanism in rat teeth is part of the hypothalamic parotid gland endocrine axis (HPEA). Infusion of a porcine hypothalamus-thalamic tissue extract (PHTE) into anesthetized rats stimulates the DFT mechanism in intact animals but is ineffective in parotidectomized rats. Infusion of PHTE into intact conscious pigs raises the plasma titer of immunoreactive PH (iPH) five- to eightfold. Parotidectomy prevents the response. The feeding of pig chow is a potent stimulus for iPH secretion: an 11-fold increase is reached within 10-20 min, and the response is directly related to the length of the feeding stimulus. No response is obtained after parotidectomy. The secretion of saliva and iPH from the parotids occurs independently of each other, suggesting different control mechanisms for each function. The immediate secretion of iPH in response to feeding and its relationship to DFT stimulation may represent a systemic physiological process by which resistance of teeth to decay is enhanced at a time when the acidogenic potential of the oral microbes is maximum.

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Galanin-Like Peptide (GALP) Is a Target for Regulation by Leptin in the Hypothalamus of the Rat

Endocrinology ◽

10.1210/endo.141.7.7669 ◽

2000 ◽

Vol 141 (7) ◽

pp. 2703-2706 ◽

Cited By ~ 40

Author(s):

Anders Juréus ◽

Matthew J. Cunningham ◽

Molly E. McClain ◽

Donald K. Clifton ◽

Robert A. Steiner

Keyword(s):

In Situ Hybridization ◽

Leptin Receptor ◽

Fold Increase ◽

Female Rats ◽

Dorsomedial Nucleus ◽

Physiological Regulation ◽

Tissue Sections ◽

Galanin Receptors ◽

Neuroendocrine Functions

Galanin-like peptide (GALP), which was recently isolated from the porcine hypothalamus, shares sequence homology with galanin and binds with high affinity to galanin receptors. To study the distribution and regulation of GALP-expressing cells in the brain, we cloned a 120 base-pair cDNA fragment of rat GALP and produced an antisense riboprobe. In situ hybridization for GALP mRNA was then performed on tissue sections throughout the forebrain of adult ovariectomized female rats. We found GALP mRNA-containing cells in the arcuate nucleus (Arc), caudal dorsomedial nucleus, median eminence and the pituitary. Because GALP mRNA in the Arc appeared to overlap with the known distribution of leptin receptor mRNA, we tested the hypothesis that GALP expression is regulated by leptin. Using in situ hybridization, we compared the number of GALP mRNA-containing cells among groups of rats that were fed ad lib or fasted for 48 h and treated with either leptin or vehicle. Fasting reduced the number of identifiable cells containing GALP mRNA in the Arc, whereas the treatment of fasted animals with leptin produced a 4-fold increase in the number of cells expressing GALP message. The presence of GALP mRNA in the hypothalamus and pituitary and its regulation by leptin suggests that GALP may have important neuroendocrine functions, including the physiological regulation of feeding, metabolism, and reproduction.

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The hibernating 13-lined ground squirrel as a model organism for potential cold storage of platelets

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00018.2012 ◽

2012 ◽

Vol 302 (10) ◽

pp. R1202-R1208 ◽

Cited By ~ 11

Author(s):

Scott T. Cooper ◽

Karl E. Richters ◽

Travis E. Melin ◽

Zhi-jian Liu ◽

Peter J. Hordyk ◽

...

Keyword(s):

Cold Storage ◽

Ground Squirrel ◽

Extreme Environments ◽

Model Organism ◽

Fold Increase ◽

Human Platelets ◽

Ground Squirrels ◽

Prolonged Storage ◽

Rapid Clearance

Hibernating mammals have developed many physiological adaptations to extreme environments. During hibernation, 13-lined ground squirrels ( Ictidomys tridecemlineatus) must suppress hemostasis to survive prolonged body temperatures of 4–8°C and 3–5 heartbeats per minute without forming lethal clots. Upon arousal in the spring, these ground squirrels must be able to quickly restore normal clotting activity to avoid bleeding. Here we show that ground squirrel platelets stored in vivo at 4–8°C were released back into the blood within 2 h of arousal in the spring with a body temperature of 37°C but were not rapidly cleared from circulation. These released platelets were capable of forming stable clots and remained in circulation for at least 2 days before newly synthesized platelets were detected. Transfusion of autologous platelets stored at 4°C or 37°C showed the same clearance rates in ground squirrels, whereas rat platelets stored in the cold had a 140-fold increase in clearance rate. Our results demonstrate that ground squirrel platelets appear to be resistant to the platelet cold storage lesions observed in other mammals, allowing prolonged storage in cold stasis and preventing rapid clearance upon spring arousal. Elucidating these adaptations could lead to the development of methods to store human platelets in the cold, extending their shelf life.

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Imunomodulator Activity of Alginate Oligosaccharides from Alginate Sargassum crassifolium

Jurnal Pengolahan Hasil Perikanan Indonesia ◽

10.17844/jphpi.v20i1.16434 ◽

2017 ◽

Vol 20 (1) ◽

pp. 63

Author(s):

Subaryono Subaryono ◽

Rosmawati Perangiangin ◽

Maggy Thenawidjaja Suhartono ◽

Fransiska Rungkat Zakaria

Keyword(s):

Biological Activities ◽

Human Lymphocytes ◽

Alginate Lyase ◽

Enzyme Concentration ◽

Degree Of Polymerization ◽

Cytotoxic T Cell ◽

Alginate Oligosaccharides ◽

Bacterium Bacillus ◽

Production Conditions

Alginate oligosaccharides (AOS) are oligosaccharides produced from depolimerization of the alginate polymer, and is reported to have various biological activities. The study aims is to determine the effect of AOS production conditions and their effects on products and its activities as an immunomodulatory compound. Production of alginate oligosaccharides (AOS) enzymatically carried out with the help of alginate lyase enzyme produced from the bacterium Bacillus megaterium S245. Variation of incubation time is 2, 4, 6 and 8 hours at concentrations of alginate lyase enzyme addition of 25, 50, 75 and 100U. Treatment of enzyme concentration and the duration of incubation in the production of AOS produces a degree of polymerization (DP) 2-7. In vitro activity test showed AOS is have ability to induce cell proliferation of human lymphocytes. This type of cell lymphocytes proliferation induced by AOS is a CD 8 cells or cytotoxic T cell and non cell CD4 / CD8. AOS production conditions with the addition of alginate lyase enzyme 50 U and incubation period 2 hours has produce AOS with the highest index of lymphocyte proliferation 117.6+3.6% or an increase of 43.24% compared to the native alginat polymer.

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Human Platelets Contain mRNA Transcripts for Platelet Factor 4 and Actin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647125 ◽

1989 ◽

Vol 62 (04) ◽

pp. 1100-1102 ◽

Cited By ~ 14

Author(s):

Jane Sottile ◽

Deane F Mosher ◽

Jan Fullenweider ◽

James N George

Keyword(s):

Cell Lines ◽

Human Cell ◽

Human Lymphocytes ◽

Human Platelets ◽

Northern Blotting ◽

Platelet Factor 4 ◽

Human Cell Lines ◽

Platelet Factor ◽

Mrna Transcripts ◽

Number Of Cells

SummaryRNAs from a number of cells, including platelets, were analyzed by Northern blotting for the presence of transcripts to four platelet proteins - actin, thrombospondin, fibronectin, and platelet factor 4. RNA from platelets contains considerable amounts of mRNA for platelet factor 4, easily detectable mRNA for actin, and traces of mRNA for thrombospondin. mRNA for platelet factor 4 was not detected in human lymphocytes or in any of 5 human cell lines.

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INFLUENCE OF CALCIUM FLUX ON STABILITY OF PLATELET MICROTUBULE COILS

10.1055/s-0038-1643904 ◽

1987 ◽

Author(s):

Gundu H R Rao ◽

James G White

Keyword(s):

Shape Change ◽

Calcium Ionophore ◽

Fold Increase ◽

Human Platelets ◽

Calcium Flux ◽

Osmic Acid ◽

Ionophore A23187 ◽

Cytoplasmic Calcium ◽

Fura 2 ◽

Morphological Studies

Resting human platelets have a characteristic discoid form supported by a circumferential microtubule (MT). Ultrastructural, immunocytochemical and immunofluorescence studies have shown that the circumferential MT is a stable structure which undergoes constriction following exposure of platelets to aggregating agents. However, some biochemical and morphological studies suggested that MT coils dissolved almost completely within seconds after exposure to aggregating agents, then reassembled 1-4 minutes later. One investigation suggested that disappearance of the MT coils was associated with calcium flux caused by agonist stimulation or exposure to the ionophore, A23187. The present study has examined the latter hypothesis directly. Fura 2, a calcium sensitive fluorophore, was loaded into washed platelets at a concentration of 1 μM, the cells washed once and resuspended in HEPES buffer. Fluorescence changes were monitored in a Fluorolog spectrofluorometer.Thrombin stimulation of Fura 2 loaded platelets resulted in an immediate eight fold increase in the level of cytoplasmic calcium. The calcium ionophore, ionomycin, stimulated a 15 fold rise in the cytoplasmic calcium of Fura 2 loaded cells.Samples of thrombin and ionomycin stimulated platelets were fixed in glutaraldehyde and osmic acid at the peak of calcium flux indicated by the rise in fluorescence. Examination of activated platelets in the electron microscope revealed shape change and internal transformation. MT coils were constricted, but did not disappear from platelets fixed during the maximum elevation of cytoplasmic calcium. The findings do not support the concept that the calcium rise produced in platelets following exposure to potent agonists causes disappearance of the circumferential MT.

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