Some enzymatic and metabolic activities of normal human erythrocytes treated in vitro with cephalothin

1. Some effects of sodium salicylate upon anaerobic glycolysis have been studied in normal human erythrocytes incubated for up to 6 h at 37°C in autologous sera. 2. Both glucose consumption and lactate production were stimulated by concentrations of salicylate up to 60 mmol/l but at the highest concentration used (90 mmol/l) an initial stimulus was followed by inhibition of glycolysis. 3. Losses occurred of adenosine 5′-triphosphate (ATP), adenosine 5′-diphosphate (ADP) and adenosine 5′-phosphate (AMP) at higher concentrations of salicylate and there was a concomitant increase of inorganic phosphate. 4. Other phosphate esters underwent concentration changes at higher concentrations of salicylate that reflected inadequate concentrations of ATP for glycolysis. 5. The rates of sodium efflux from, and potassium influx into, erythrocytes were unaffected by the presence of salicylate at concentrations sufficient to stimulate glycolysis.

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The Effects of Cisplatin on Normal Human Erythrocytes in Vitro

Scandinavian Journal of Haematology ◽

10.1111/j.1600-0609.1983.tb00654.x ◽

2009 ◽

Vol 31 (3) ◽

pp. 283-286 ◽

Cited By ~ 3

Author(s):

Margaret Dawson ◽

Esther A. Brown ◽

Ronald D. Barr

Keyword(s):

Human Erythrocytes ◽

Normal Human

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Role of human decay-accelerating factor in the evasion of Schistosoma mansoni from the complement-mediated killing in vitro.

Journal of Experimental Medicine ◽

10.1084/jem.174.6.1399 ◽

1991 ◽

Vol 174 (6) ◽

pp. 1399-1406 ◽

Cited By ~ 38

Author(s):

M F Horta ◽

F J Ramalho-Pinto ◽

M Fatima

Keyword(s):

Schistosoma Mansoni ◽

Acquired Resistance ◽

Surface Protein ◽

Human Erythrocytes ◽

Membrane Glycoprotein ◽

Decay Accelerating Factor ◽

Normal Human

Decay-accelerating factor (DAF) is a 70-kD membrane glycoprotein that prevents complement (C)-mediated hemolysis by blocking the assembly or accelerating the decay of C3 convertase. Purified DAF is known to incorporate into the membrane of DAF-deficient cells, inhibiting lysis. Since Schistosoma mansoni is a blood-dwelling parasite, we investigated whether DAF can be transferred from human erythrocytes to the worm and protect it against C-mediated killing in vitro. We have found that schistosomula (schla) incubated with normal human erythrocytes (N-HuE), but not with DAF-deficient erythrocytes, become resistant to C damage in vitro. Protected parasites acquire a 70-kD surface protein which can be immunoprecipitated by anti-DAF antibodies. The acquired resistance is abrogated by treatment of N-HuE-incubated parasites with anti-DAF antibody. These results indicate that, in vitro, N-HuE DAF can be transferred to schla, and suggest its participation in preventing their C-mediated killing. This could represent an important strategy of parasites to evade the host's immune response in vivo.

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THE EFFECT OF ACTH AND ADRENAL STEROIDS ON K TRANSPORT IN HUMAN ERYTHROCYTES

The Journal of General Physiology ◽

10.1085/jgp.37.5.643 ◽

1954 ◽

Vol 37 (5) ◽

pp. 643-661 ◽

Cited By ~ 56

Author(s):

D. H. P. Streeten ◽

A. K. Solomon

Keyword(s):

Human Erythrocytes ◽

Adrenal Steroids ◽

Method Of Calculation ◽

Normal Human ◽

K Concentration ◽

The Relationship ◽

K Transport ◽

External K

The effect of ACTH and adrenal steroids on K transport in human erythrocytes has been studied. A new method of calculation has revealed that in normal human erythrocytes the K transport is not independent of external K concentration as had previously been thought. The equation describing the relationship is, K influx (m.eq./liter cells hour) = [K]pi/(0.697 + 0.329 [K]pi) in which [K]pi refers to the plasma K concentration at the beginning of the experiment. At the physiological plasma K concentration of 4.65 m.eq./liter, K influx is 2.09 m.eq./liter cells hour; K efflux is 1.95 m.eq./liter cells hour and is independent of plasma K concentration. The effect of the infusion of ACTH and adrenal steroids on the K content of the erythrocytes was also studied. Infusions of ACTH or cortisone do not cause the expected loss in erythrocyte K content and may well cause a gain. Infusions of ACTH and cortisone decrease the rate of K influx and efflux slightly at all stages of the infusion, as measured in vitro in blood samples drawn at various times during and following the infusion. However, the erythrocytes incubated in vitro do not exhibit the same changes in K content as are found in vivo. Hydrocortisone added to normal cells in vitro also decreases both influx and efflux of K, without affecting the K content of the cells.

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Presence and Possible Origin of ɛ(γ-Glutamyl)Lysine Isodipeptide in Human Plasma

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648380 ◽

1992 ◽

Vol 67 (01) ◽

pp. 060-062 ◽

Cited By ~ 9

Author(s):

J Harsfalvi ◽

E Tarcsa ◽

M Udvardy ◽

G Zajka ◽

T Szarvas ◽

...

Keyword(s):

Human Plasma ◽

Fibrinolytic Therapy ◽

Normal Human Plasma ◽

Normal Human ◽

Hplc Technique ◽

Significant Change

Summaryɛ(γ-glutamyl)lysine isodipeptide has been detected in normal human plasma by a sensitive HPLC technique in a concentration of 1.9-3.6 μmol/1. Incubation of in vitro clotted plasma at 37° C for 12 h resulted in an increased amount of isodipeptide, and there was no further significant change when streptokinase was also present. Increased in vivo isodipeptide concentrations were also observed in hypercoagulable states and during fibrinolytic therapy.

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Inhibition of the Activities of α2-Plasmin inhibitor (PI) and CI inhibitor (CI-Inh) by the Synthetic Fibrinolytic Agent, 3-Hydroxypropyl Flufenamide (Flu-HPA)

10.1055/s-0038-1665785 ◽

1979 ◽

Author(s):

L Miles ◽

J Burnier ◽

M Verlander ◽

M Goodman ◽

A Kleiss ◽

...

Keyword(s):

Plasminogen Activators ◽

Inhibitory Effect ◽

Mechanisms Of Action ◽

Flufenamic Acid ◽

Clot Lysis ◽

Factor Xiia ◽

Dependent Inhibition ◽

Normal Human ◽

Plasmin Inhibitor

Flu-HPA is one of a series of flufenamic acid derivations that enhances plasminogen-dependent clot lysis in vitro. Studies of possible mechanisms of action of Flu-HPA were undertaken. The influence of Flu-HPA on the inhibition of purified plasmin by purified PI was studied. PI activity was assessed by its inhibition of the clevage of the tripeptide S-2251 (H-D-Val-Leu-Lys-pNA) by plasmin. Flu-HPA was dissolved in DMF or in methonol and preincubated with PI before addition of plasmin. At Flu-HPA concentrations greater than 1mM and up to 60mM, the inhibitory activity of PI was totally lost. The inhibitory effect of normal human plasma on plasmin was also completely abolished at concentrations of Flu-HPA between 2.5 and 40mM. The effect of Flu-HPA on the inhibition of purified plasma kallikrein by purified CI-Inh was also studied. CI-Inh activity was measured by its inhibition of cleavage of the tripeptide Bz-Pro-Phe-Arg-pNA by kallikrein. When Flu-HPA, dissolved in DMF or in methonol, was preincubated with CI-Inh, a concentration dependent inhibition of CI-Inh activity was observed. CI-Inh activity was abolished by concentrations of Flu-HPA greater than 1mM. Flu-HPA also inhibited the activity of CI-Inh on purified Factor XIIa. These observations suggest that this flufenamic acid derivative may enhance fibrinolysis not only by inhibiting PI activity but also by decreasing the inactivation of plasminogen activators by CI-Inh.

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IN VITRO UPTAKE OF RADIOACTIVE 131I LABELLED L-TRIIODOTHYRONINE BY HUMAN ERYTHROCYTES AS AN INDEX OF THYROID FUNCTION

Acta Endocrinologica ◽

10.1530/acta.0.xxxiv0305 ◽

1960 ◽

Vol XXXIV (II) ◽

pp. 305-311 ◽

Cited By ~ 3

Author(s):

M. G. Woldring ◽

A. Bakker ◽

H. Doorenbos

Keyword(s):

Thyroid Function ◽

Incubation Time ◽

Clinical Results ◽

Human Erythrocytes ◽

Red Cell ◽

Clinical Value ◽

Blood Samples ◽

In Vitro Uptake

ABSTRACT The red cell triiodothyronine uptake technique as used in our hospital is described. Incubation time is of almost no importance. The temperature during incubation should be 37° C. Further improvement of the technique is obtained when all blood samples are brought up to 40 % haematocrit prior to incubation. Clinical results are discussed. It is yet too early to give a definite assessment of its clinical value, but it is definitely superior to the measurement of the BMR.

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Preparation and In Vitro Evaluation of Resealed Erythrocytes as A New Trend in Treatment of Asthma

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v6i3.8889 ◽

2016 ◽

Vol 6 (3) ◽

Author(s):

Mohammed Ibrahim ◽

Alaa Zaky ◽

Mohsen Afouna ◽

Ahmed Samy

Keyword(s):

In Vitro Release ◽

Human Erythrocytes ◽

The Body ◽

Blood Levels ◽

Time Interval ◽

Burst Release ◽

Prolonged Release ◽

Nocturnal Asthma ◽

Carrier Erythrocytes

Carrier erythrocytes are emerging as one of the most promising biological drug delivery systems investigated in recent decades. Beside its biocompatibility, biodegradability and ability to circulate throughout the body, it has the ability to perform extended release system of the drug for a long period. The ultimate goal of this study is to introduce a new carrier system for Salbutamol, maintaining suitable blood levels for a long time, as atrial to resolve the problems of nocturnal asthma medication Therefore in this work we study the effect of time, temperature as well as concentration on the loading of salbutamol in human erythrocytes to be used as systemic sustained release delivery system for this drug. After the loading process is performed the carrier erythrocytes were physically and cellulary characterized. Also, the in vitro release of salbutamol from carrier erythrocytes was studied over time interval. From the results it was found that, human erythrocytes have been successfully loaded with salbutamol using endocytosis method either at 25 Co or at 37 Co . The highest loaded amount was 3.5 mg/ml and 6.5 mg/ml respectively. Moreover, the percent of cells recovery is 90.7± 1.64%. Hematological parameters and osmotic fragility behavior of salbutamol loaded erythrocytes were similar that of native erythrocytes. Scanning electron microscopy demonstrated that the salbutamol loaded cells has moderate change in the morphology. Salbutamol releasing from carrier cell was 43% after 36 hours in phosphate buffer saline. The releasing pattern of the drug from loaded erythrocytes showed initial burst release in the first hour followed by a very slow release, obeying zero order kinetics. It concluded that salbutamol is successfully entrapped into erythrocytes with acceptable loading parameters and moderate morphological changes, this suggesting that erythrocytes can be used as prolonged release carrier for salbutamol.

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Integrating Biosensors in Organs-on-Chip Devices: A Perspective on Current Strategies to Monitor Microphysiological Systems

Biosensors ◽

10.3390/bios10090110 ◽

2020 ◽

Vol 10 (9) ◽

pp. 110 ◽

Cited By ~ 2

Author(s):

Erika Ferrari ◽

Cecilia Palma ◽

Simone Vesentini ◽

Paola Occhetta ◽

Marco Rasponi

Keyword(s):

Imaging Techniques ◽

Biological Models ◽

Electromechanical Properties ◽

Human Organs ◽

Tissue Constructs ◽

Microphysiological Systems ◽

Metabolic Activities ◽

On Chip ◽

Chip Analysis

Organs-on-chip (OoC), often referred to as microphysiological systems (MPS), are advanced in vitro tools able to replicate essential functions of human organs. Owing to their unprecedented ability to recapitulate key features of the native cellular environments, they represent promising tools for tissue engineering and drug screening applications. The achievement of proper functionalities within OoC is crucial; to this purpose, several parameters (e.g., chemical, physical) need to be assessed. Currently, most approaches rely on off-chip analysis and imaging techniques. However, the urgent demand for continuous, noninvasive, and real-time monitoring of tissue constructs requires the direct integration of biosensors. In this review, we focus on recent strategies to miniaturize and embed biosensing systems into organs-on-chip platforms. Biosensors for monitoring biological models with metabolic activities, models with tissue barrier functions, as well as models with electromechanical properties will be described and critically evaluated. In addition, multisensor integration within multiorgan platforms will be further reviewed and discussed.

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The Effect of Practolol, In Vitro Generated Metabolites of Practolol and Chemical Analogues on the Rate of Growth of Human Skin Fibroblasts

Alternatives to Laboratory Animals ◽

10.1177/026119298401200205 ◽

1984 ◽

Vol 12 (2) ◽

pp. 89-97

Author(s):

Graham R. Elliott ◽

H.E. Amos ◽

James W. Bridges

Keyword(s):

Human Skin ◽

Psoriasis Patient ◽

Skin Fibroblasts ◽

Human Skin Fibroblasts ◽

Cell Type ◽

Normal Human Skin ◽

Rate Of Growth ◽

Structural Analogues ◽

Normal Human

The rate of growth of normal human skin fibroblasts was inhibited in a dose related, reversible, fashion by practolol (N-4-(2-hydroxy)-3 (1-methyl)-aminopropoxyphenylacetamine) (ID50 1.35 ± 0.14 x 10-3M), propranolol (1-(isopropylamino)-3(1-naphthyl-oxy)-2-propranolol) (ID50 0.145 ± 0.02 x 10-3M) and paracetamol (N-(4-hydroxyphenyl) acetamide) (ID50 0.85 ± 0.2 x 10-3M). Skin fibroblasts isolated from a psoriasis patient were more sensitive towards practolol (ID50 0.48 ± 0.14 x 10-3M) and propranolol (ID50 0.032 ± 0.002 x 10-3M), but less sensitive towards paracetamol (ID50 1.3 ± 0.07 x 10-3M). In vitro generated metabolites of practolol, using normal or Arochlor 1254-pretreated hamster liver preparations, and structural analogues of practolol had no effect upon the growth of either cell type.

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