scholarly journals Study of pharmacokinetics of liposomal photosensitiser based on hydroxyaluminium tetra-3-phenylthiophthalocyanine on mice

2019 ◽  
Vol 7 (4) ◽  
pp. 16-22 ◽  
Author(s):  
A. P. Budko ◽  
Z. G. Deichman ◽  
G. A. Meerovich ◽  
L. M. Borisova ◽  
I. G. Мeerovich ◽  
...  

The present work is devoted to the study of pharmacokinetics of infrared photosensitizer (PS) based on hydroxyaluminium tetra‑3‑phenylthiophthalocyanine in a sterically stabilized liposomal form. The study was carried out on adult female mice. The PS was administered once intravenously at a dose of 6 mg / kg. Evaluation of the PS accumulation dynamics in the mice tissues and organs was performed at time intervals from 5 minutes to 7 days using spectral‑fluorescent method. The maximum accumulation of the PS photoactive form was recorded in lungs (32 µg / g in the interval of 5–30 minutes after introduction), liver (20.8 µg / g in the interval of 4–24 hours after introduction) and spleen (28 µg / g 4 hours after introduction). At the same time, by the end of the observation period (7 days after administration), trace amounts of the PS photoactive form were still detected in the liver and the spleen at a calculated concentration of 0.5‑1 µg / g. The PS accumulated the least in muscles and skin. The fluorescent signal from the PS accumulated in skin was detectable almost immediately, and its concentration remained at the same level (1.2‑1.5 µg / g) for up to 3 days of observation. In the muscles, the concentration of the PS reached 1.5 µg / g 15 minutes after administration, and then gradually decreased until 0.25 µg / g at 24 hours. Data on the pharmacokinetics of PS in blood, basic organs and tissues of animals were obtained, pharmacokinetic parameters were calculated. 7 days after the administration, the PS concentration in the skin and muscles was below the detection limit. The studies confrmed that PEGylation of the PS liposomal form slows down the process of its capture by reticulo‑endothelial system. It was shown that the PS circulates in blood and organs of mice for a long time and it completely distributes only when 4 hours pass after administration.

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.


Author(s):  
Masahiro Ishibashi

It is shown that critical flow Venturi nozzles need time intervals, i.e., more than five hours, to achieve steady state conditions. During these intervals, the discharge coefficient varies gradually to reach a value inherent to the pressure ratio applied. When a nozzle is suddenly put in the critical condition, its discharge coefficient is trapped at a certain value then afterwards approaches gradually to the inherent value. Primary calibrations are considered to have measured the trapped discharge coefficient, whereas nozzles in applications, where a constant pressure ratio is applied for a long time, have a discharge coefficient inherent to the pressure ratio; inherent and trapped coefficients can differ by 0.03–0.04%.


2009 ◽  
Vol 24 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Dragica Brkic ◽  
Slavica Gasic ◽  
Nesko Neskovic

An acute oral toxicity study of the herbicide GAL-57 (Avalon), a mixture of bentazon and dicamba as active ingredients, was investigated on rats, using a new method that has been used in the past several years (2001). Clinical observations symptoms and mortality were performed for all animals in different time intervals after treatment, and gross necropsy was performed at the end of observation period. Clinical symptoms (decreased activity, prone position, abnormal limb position, decreased righting reflex, decreased grip and limb tone, decreased body and abdominal tone, dyspnoea) of marked degree were noted after administration of 2000 mg/kg, and animals were dead in the period of 30-60 minutes after the treatment. GAL-57 did not cause any clinical sings at single 300 mg/kg bw dose. The physical condition and behavior of animals (males and females) were normal, and it is not differ in reaction to the control. According to the methodology used in the present study, it could be concluded that the acute oral LD-50 value of the GAL-57 proved to be between 300 and 2000 mg/kg body weight in rats, and the product was ranked into Poison group III according to Serbian criteria, category 4 of the Global Harmonized Classification System, and Category III of the EPA classification.


Agriculture ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 245
Author(s):  
František Zigo ◽  
Nad’a Sasáková ◽  
Gabriela Gregová ◽  
Jana Výrostková ◽  
Silvia Ondrašovičová

The aim of this study was to compare an improved bedding composition with conventional straw bedding under farm conditions, regarding its effects on the influence of indicator microorganisms on the hygiene levels of cubicle floors and the occurrence of mastitis in dairy cows. Dairy cows were housed in newly built stalls divided into two parts, each with four subsections, and bedded cubicles arranged in three rows. Five stall subsections from each 9-bedded cubicle were selected for study, and 30 dairy cows were monitored according to the time intervals of bedding treatment for cubicles. In the first subsection (control), the cows were housed in bedded cubicles layered with straw up to a height of 20 cm. Sections 2–5 had alternative bedding (AB) as follows: fresh AB, AB 1 month old, AB 2 months old, and AB 3 months old, which were bedded one day before (fresh) and 1–3 months before the actual observation period, respectively. The alternative bedding per one cubicle consisted of ground limestone (100 kg), water (80 L), recycled manure solids (RMS; 15 kg), and straw (25 kg). After laying, the bedding was treated with a concrete selector to provide strength and sufficient resistance. A total of 180 bedding and 600 quarter milk samples were taken simultaneously from all five monitored subsections for microbiological determination. Comparing classical straw bedding with the alternate bedding showed a stabilizing effect by keeping the bedding thickness up to the floor barrier level, which had a beneficial effect by reducing the level of fecal contamination in the rear of the cubicle. Fecal coliforms and fecal streptococci were found to be reduced in one-day-old bedding as well as after the first, second, and third months. By evaluating the health status of the mammary glands, a positive effect was noted in reducing the occurrence of subclinical mastitis, which was reflected in a reduced number of infected quarters in the group of cows housed in cubicles for three months after use of improved bedding.


1984 ◽  
Vol 106 (3) ◽  
pp. 362-368
Author(s):  
J. F. Kiefner ◽  
T. P. Forte

An analytical model is presented for predicting hydrostatic retest intervals in liquid pipelines which are subjected to frequent large pressure cycles. The model utilizes pressure cycle history, hydrostatic test history, and fatigue crack growth rate data for the pipe material to calculate time to failure for the largest possible defect which could have survived a previous hydrostatic test. An example problem is described which shows the value of maximizing the margin between test pressure and operating pressure in order to achieve long time intervals between tests.


This lecture is an attempt to review current knowledge about certain terrestrial phenomena with the twofold purpose: ( a ) to discover the extent to which the behaviour of the Earth may be influenced by fluctuations in its astronomical environment, ( b ) to see if new knowledge of that environment may be gained from its influence on the Earth. Fluctuations in geomagnetism, climate, glaciation, biological extinctions, etc., are surveyed with special regard to datings and characteristic time-intervals; correlations between such fluctuations are discussed. Astronomical phenomena, within the Solar System and elsewhere in the Galaxy, that might cause terrestrial effects are reviewed. As regards astronomical effects on Earth: (i) There is a good case - not yet overwhelming - for the currently widely accepted view that fluctuations of glaciation within an ice-epoch result from changes of insolation accompanying fluctuations of the Earth’s motion relative to the Sun. Some evidence suggests that an ice-epoch may be triggered by variations of the astronomical environment encountered in the Sun’s motion relative to the Galaxy; but tectonic changes on Earth may be the main trigger. (ii) Impacts of planetesimals may be more important than hitherto recognized. Among astronomical results regarding the Sun, while the intensity of solar ‘activity’ is variable, terrestrial effects provide no confirmation that the Sun is a ‘variable star’. Regarding the Galaxy, impacting planetesimals may originate in interstellar clouds, and so provide on Earth samples of interstellar matter. Some unsolved problems emphasized by the review are listed; certain concepts that would call for consideration in any extended review are mentioned.


2013 ◽  
Vol 10 (88) ◽  
pp. 20130630 ◽  
Author(s):  
Lucie G. Bowden ◽  
Matthew J. Simpson ◽  
Ruth E. Baker

Cell trajectory data are often reported in the experimental cell biology literature to distinguish between different types of cell migration. Unfortunately, there is no accepted protocol for designing or interpreting such experiments and this makes it difficult to quantitatively compare different published datasets and to understand how changes in experimental design influence our ability to interpret different experiments. Here, we use an individual-based mathematical model to simulate the key features of a cell trajectory experiment. This shows that our ability to correctly interpret trajectory data is extremely sensitive to the geometry and timing of the experiment, the degree of motility bias and the number of experimental replicates. We show that cell trajectory experiments produce data that are most reliable when the experiment is performed in a quasi-one-dimensional geometry with a large number of identically prepared experiments conducted over a relatively short time-interval rather than a few trajectories recorded over particularly long time-intervals.


Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 360-365 ◽  
Author(s):  
G. T. Cook ◽  
E. M. Scott ◽  
E. M. Wright ◽  
Robert Anderson

We consider the suitability of commonly used Poisson counting statistics applied to background count rates measured in the new generation of low-background Packard liquid scintillation spectrometers. We also investigate the stability of these systems over long time intervals. Undetected instability will result in an underestimation of the precision of any result (i.e., the calculated error will be too small), and, in the presence of a systematic source, could lead to inaccurate results. The work described here forms only a small part of a project to investigate the statistical criteria that should be applied to the performance of such counters. The procedures to be discussed here include the Poisson index of dispersion, x and s control charts and the MSSD test for detection of drift. These are illustrated on background count rates derived from the Packard 2260XL and 2000CA/LL.


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