10 IN VITRO PROGESTERONE RELEASE KINETICS: A COMPARATIVE STUDY OF DIFFERENT INTRAVAGINAL DEVICES USED IN CATTLE

2011 ◽  
Vol 23 (1) ◽  
pp. 111
Author(s):  
G. C. Gomes ◽  
A. Kehrle ◽  
M. Maturana Filho ◽  
C. V. F. Caetano ◽  
J. R. V. Pimentel ◽  
...  
Keyword(s):  
Statistical Difference ◽  
Release Kinetics ◽  
In Vitro Tests ◽  
Water Mixture ◽  
The Third ◽  
Metabolism Rate ◽  
Alcohol Water ◽  
Reproduction Cost ◽  
Second Use

Since progesterone releasing devices have been used for oestrous cycle control, many studies have been done to evaluate the reduce reproduction cost. However, there are few studies about reused devices. The aim of this study was to evaluate and compare in vitro P4 releasing kinetics from 3 commercially available devices: Sincrogest® (SIN, 1 g of P4), Cronipres® (CRO, 1 g of P4 and 3 rings of 0.1 g of P4 for the third use), and Primer® (PRI, 1 g of P4). For each device, new (first use, n = 2), once-used (second use, n = 2), and twice-used (third use, n = 2) devices were tested. The tests were performed in a dissolutor sink using an alcohol/water mixture (60/40, vol/vol) as a release media. Samples were collected at 0–24 h (1P), 24–48 h (2P), 48–72 h (3P), and 72–96 h (4P). Table 1 shows the P4 amount (mg) and standard deviation in the periods in which there was statistical difference (P < 0.05; a–cdifferent letters in the same period differ statistically). The 3 brands of P4 devices differ in 2 of 4, 3 of 4, and 1 of 4 intervals for 1st-, 2nd, and 3rd-use device tests respectively. Additionally, P4 release decreased according to the number of previous uses. It is known that in vitro tests are more sensible to detect differences between devices. Nevertheless, these findings suggest the possibility of targeting different device categories for different animal categories depending on the animal steroid metabolism rate and consequent need for exogenous P4. However, for such a claim, further studies on this topic are needed. Table 1.Comparison between the 3 types in each of 3 uses Supported by FAPESP – Fundação de Amparo a Pesquisa do estado de São Paulo.

15 IN VIVO PROGESTERONE RELEASE KINETICS: A COMPARATIVE STUDY OF DIFFERENT INTRAVAGINAL DEVICES USED IN CATTLE

2011 ◽  
Vol 23 (1) ◽  
pp. 114 ◽  
Author(s):  
M. Maturana Filho ◽  
G. C. Gomes ◽  
C. V. F. Caetano ◽  
A. Kehrle ◽  
P. H. P. Miguez ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Release Kinetics ◽  
Plasma Concentrations ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
The Third ◽  
Metabolism Rate ◽  
Experimental Group ◽  
Second Use

Intravaginal progesterone (P4) releasing devices are widely used in hormonal protocols for fixed-time artificial insemination (FTAI). To reduce production cost in Brazilian farms, after first use these devices are currently reused once or twice, providing good reproductive efficiency in cattle. The aim of this study was to compare P4 plasma concentrations among time in ovariectomized cows receiving 3 different commercially available devices: Sincrogest® (SIN, 1 g of P4), Cronipres® (CRO, 1 g of P4 and 3 rings of 0,1 g of P4 for the third use) and Primer® (PRI, 1 g of P4). For each type, new (1st use, n = 2), once-used (2nd use, n = 2) and twice-used (3rd use, n = 2) devices were tested. Blood samples were collected at times 0 (before device insertion), 2, 4, 8, 10, 12, 24, 48, 72, 96, 120, 144, 168, and 192 h (Day 0 to Day 8). P4 plasma concentrations were measured by radioimmunoassay and the averages for each experimental group were submitted to analysis of variance adding repeated-measures in time factor. Comparisons were made among 3 types of device in each of 3 uses. P4 concentrations (ng mL–1) and standard deviation in the periods in which there was statistical difference (P < 0.05; a,b,cdifferent letters in the same period differ statistically) were as follows: First use: the 3 brands did not differ during the test and in Day 8 P4 levels remained near 2 ng mL–1. Second use: 2 h – SIN (3.7 ± 0.8)ab, CRO (5.4 ± 0.4)a, PRI (3 ± 0.4)b; 6 h – SIN (4 ± 0.5)a, CRO (4.9 ± 0.2)a, PRI (2.9 ± 0.3)b; and 144 h – SIN (2.2 ± 0.4)b, CRO (0.8 ± 0.3)a, PRI (1.3 ± 0.1)ab. On Day 8, Primer® and Sincrogest® P4 levels remained between 1 and 2 ng mL–1, whereas Cronipres® levels remained below 1 ng mL–1. Third use: 2 h – SIN (3.2 ± 0.04)b, CRO (7.9 ± 0.5)a, PRI (2.4 ± 0.2)b; 4 h – SIN (2.4 ± 0.4)b, CRO (5.4 ± 0.2)a, PRI (2.8 ± 0.3)b; 6 h – SIN (2.5 ± 0.8)b, CRO (7.4 ± 1.8)a, PRI (2.7 ± 0.5)b; 8 h – SIN (2.3 ± 0.2)b, CRO (5.3 ± 1.4)a, PRI (2 ± 0.1)b; 10 h – SIN (3.1 ± 0.2)b, CRO (5.5 ± 0.5)a, PRI (2.5 ± 0.2)b. 12 h – (2.7 ± 1.3)b, CRO (5.8 ± 0.6)a, PRI (2.2 ± 0,1)b; and 120 h – SIN (1.3 ± 0.2)a, CRO (0.9 ± 0.2)b, PRI (0.8 ± 0.04)b. On Day 8, all levels remained below 1 ng mL–1. In this study, P4 released concentrations differed in 3 of 15 periods in second-use device tests. In third-use device tests, Cronipres® released significantly more P4 from 2 to 12 h. It is unclear, however, if greater release of P4 in the first 24 h is advantageous, considering that Sincrogest and Primer® P4 concentrations remained above 2 ng mL–1. Additionally, it was noticed that P4 release decreased according to the number of previous uses. These findings suggest a variety of possibilities matching different device brands and different animal categories depending on animal steroid metabolism rate and consequent need for exogenous P4 supplementation. However, for such a claim, further studies on this topic are needed. Supported by FAPESP – Fundação de Amparo à Pesquisa do estado de São Paulo.

A Summary of the Third Global Interferon-γ Release Assay Symposium

2013 ◽  
Vol 34 (6) ◽  
pp. 619-624 ◽  
Author(s):  
Antonino Catanzaro ◽  
Charles Daley
Keyword(s):  
Immune Response ◽  
Tuberculin Skin Test ◽  
Skin Test ◽  
Interferon Γ ◽  
Enzyme Linked Immunosorbent Assay ◽  
In Vitro Tests ◽  
The Third ◽  
Specific Antigens ◽  
Ifn Γ

Studies over the past several decades have dramatically increased our understanding of the immune response to Mycobacterium tuberculosis infection, and advances in proteomics and genomics have led to a new class of immune-diagnostic tests, termed interferon-γ (IFN-γ) release assays (IGRAs), which appear to obviate many of the problems encountered with the tuberculin skin test (TST). Worldwide, 2 IGRAs are currently commercially available. QuantiFERON-TB Gold In-Tube (Cellestis) is a third-generation product that uses an enzyme-linked immunosorbent assay to measure IFN-γ generated in whole blood stimulated with M. tuberculosis–specific antigens. T-Spot-TB (Oxford Immunotec) employs enzyme-linked immunosorbent spot technology to enumerate the number of purified lymphocytes that respond to M. tuberculosis–specific antigens by producing IFN-γ. These in vitro tests measure the host immune response to M. tuberculosis–specific antigens, which virtually eliminates false-positive cross reactions caused by bacillus Calmette-Guérin vaccination and/or exposure to environmental nontuberculous mycobacteria that plague the interpretation and accuracy of the tuberculin skin test (TST). The high specificity of IGRAs, together with sensitivity commensurate with or better than that of the TST, promises an accurate diagnosis and the ability to focus tuberculosis-control activities on those who are actually infected with M. tuberculosis. The Third Global Symposium was held over a 3-day period and was presented by the University of California, San Diego, Continuing Medical Education department; slides and sound recordings of each presentation are available at http://cme.ucsd.edu/igras/syllabus.html. A moderated discussion is also available at http://cme.ucsd.edu/igrasvideo. This document provides a summary of the key findings of the meeting, specifically focusing on the use of IGRAs in screening healthcare worker populations.

scholarly journals Double-Walled Poly-(D,L-lactide-co-glycolide) (PLGA) and Poly(L-lactide) (PLLA) Nanoparticles for the Sustained Release of Doxorubicin

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3230
Author(s):  
M. Margarida Cardoso ◽  
Inês N. Peca ◽  
Telma Lopes ◽  
Rui Gardner ◽  
A. Bicho
Keyword(s):  
Rate Control ◽  
Release Kinetics ◽  
Drug Distribution ◽  
In Vitro Tests ◽  
Cellular Viability ◽  
Release Rates ◽  
Zero Order Release ◽  
Evaporation Technique ◽  
Model Drug

Double-walled nanoparticles (DWNPs), containing doxorubicin as a model drug, were produced using poly-(D,L-lactide-co-glycolide) (PLGA) and poly(L-lactide) (PLLA) by the solvent evaporation technique. Double-walled microparticles containing doxorubicin were also produced to make possible the examination of the inner morphology and drug distribution using optical and fluorescence microscopy. The produced microparticles present a double-walled structure with doxorubicin solubilized in the PLGA-rich phase. The DWNPs produced present very low initial burst values and a sustained DOX release for at least 90 days with release rates decreasing with the increase in the PLLA amount. Zero-order release kinetics were obtained after day 15. The results support that the PLLA layer acts as a rate control barrier and that the diffusion of doxorubicin from the drug-loaded inner PLGA core can be retarded by an increase in the thickness of the unloaded outer layer. The unloaded double-walled nanoparticles produced were used in in vitro tests with CHO cells and demonstrate that they are nontoxic, while the double-walled nanoparticles loaded with doxorubicin caused a great cellular viability and decreased when tested in vitro.

scholarly journals In vitro Release Kinetics of Progesterone from Biodegradable In situ Implant System

1970 ◽  
Vol 6 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Irin Dewan ◽  
Md Elias-Al-Mamun ◽  
Reza-ul Jalil
Keyword(s):  
Release Kinetics ◽  
Drug Loading ◽  
Static Condition ◽  
Surrounding Tissue ◽  
In Vitro Dissolution ◽  
Release Mechanism ◽  
Water Mixture ◽  
Biodegradable Implant

In situ implants containing Progesterone (PRG) were prepared by using biodegradable Poly (DLlactide- co-glycolide) polymer. Dimethyl sulfoxide (DMSO) was used as an aprotic solvent in this implant formulation. This system was prepared by dissolving a water insoluble and biodegradable polymer (PLGA) in a biocompatible organic solvent (DMSO) and then the drug progesterone was added to the polymer solution to produce the drug solution. When the PLGA-PRG solution (0.5 ml) was injected subcutaneously into rat (weight 130g), the solvent dissipated into the surrounding tissue leading phase separation and subsequent coagulation of the polymer & drug to form an implant in situ. The implants were removed from the rat after one hour and stored in freezing condition. The digital photographs of the in-situ formed implants obtained after 1hour shows the evidence of the formation of the implants. Two formulations of implants were made. One contained 10% of progesterone and the other 20%. In vitro dissolution studies of progesterone was performed at static condition in ethanol-water mixture (30:70) at 37°C for 30 days. The implants of 20% progesterone loading showed about 65% release and the implants of 10% loading showed 56% release within 30 days. The release mechanism from these implants resembles closely to Higuchian pattern and first order. The release rate was found faster from the implants with higher drug loading of 20% progesterone, compared to implants of 10% drug loading. Key words: Biodegradable; Implant; Biocompatible; Sustained Release Dhaka Univ. J. Pharm. Sci. 6(2): 99-103, 2007 (December)

Design and Charecterization of Anticancer Engineered Resealed Erythrocytes

1970 ◽  
Vol 1 (3) ◽  
pp. 243-250
Author(s):  
R. C. Doijad ◽  
N. V. Deshmukh ◽  
D. S. Bhambere ◽  
Rony Joseph ◽  
F. V. Manvi
Keyword(s):  
Targeted Delivery ◽  
Release Kinetics ◽  
Reticuloendothelial System ◽  
Sem Analysis ◽  
In Vitro Tests ◽  
Mean Corpuscular Hemoglobin ◽  
Laser Scattering ◽  
Zero Order Kinetics ◽  
Model Drug

A number of investigators have been focusing their attention on the encapsulation of antineoplastic drugs within erythrocytes to diminish their side effects. In this study, human erythrocytes have been loaded by methotrexate (MTX) as a model drug using hypotonic hemolysis method for targeted delivery of this drug. A series of in vitro tests have been carried out to characterize the carrier cells in vitro, including loading parameters, hemoglobin release kinetics, particle size distribution, SEM analysis, osmotic and turbulence fragilities. Carrier erythrocytes having acceptable loading parameters, released their drug content according to zero-order kinetics. Mean corpuscular hemoglobin content values of the cells decreased, the apparent cell sizes measured using dynamic laser scattering, were not significantly different from normal erythrocytes, but the real sizes, measured using SEM, and surface topologies were quite different between loaded and unloaded cells. The MTX-loaded cells were remarkably more fragile compared to the normal cells. Drug loaded erythrocytes showed preferential drug targeting to liver followed by lungs, kidney and spleen. Totally, MTX-loaded erythrocytes seem to be a promising delivery system for targeting the drug to reticuloendothelial system (RES).

Anti-Diabetic Activity of a Mineraloid Isolate, in vitro and in Genetically Diabetic Mice

2011 ◽  
Vol 81 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Joel Deneau ◽  
Taufeeq Ahmed ◽  
Roger Blotsky ◽  
Krzysztof Bojanowski
Keyword(s):  
Dna Microarrays ◽  
Human Fibroblasts ◽  
Diabetic Animal ◽  
In Vitro Tests ◽  
Diabetic Mice ◽  
Fossil Material ◽  
Expression Of Genes ◽  
Enhanced Expression ◽  
Genetically Diabetic Mice

Type II diabetes is a metabolic disease mediated through multiple molecular pathways. Here, we report anti-diabetic effect of a standardized isolate from a fossil material - a mineraloid leonardite - in in vitro tests and in genetically diabetic mice. The mineraloid isolate stimulated mitochondrial metabolism in human fibroblasts and this stimulation correlated with enhanced expression of genes coding for mitochondrial proteins such as ATP synthases and ribosomal protein precursors, as measured by DNA microarrays. In the diabetic animal model, consumption of the Totala isolate resulted in decreased weight gain, blood glucose, and glycated hemoglobin. To our best knowledge, this is the first description ever of a fossil material having anti-diabetic activity in pre-clinical models.

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

1976 ◽  
Vol 35 (02) ◽  
pp. 350-357 ◽  
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.

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

A Comparison of the in Vitro and in Vivo Thrombogenic Activity of Factor IX Concentrates Using Stasis (Wessler) and Non-Stasis Rabbit Models

1980 ◽  
Vol 44 (02) ◽  
pp. 081-086 ◽  
Author(s):  
C V Prowse ◽  
A E Williams
Keyword(s):  
Platelet Rich Plasma ◽  
Thrombus Formation ◽  
Factor Ix ◽  
Coagulation System ◽  
In Vitro Tests ◽  
Clinical Use ◽  
Low Activity

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

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