Microbial Subversion of Immunity: Peter Lachmann · | Books Express

Helminth immune evasion. Page 12 | Medical microbiology & virology | intellicig.ro

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Redactorresponsabil: Prof. In order to evaluate the method of separation, purification and derivatization of testosterone in blood plasma was used internal standard procedure.

Plasma testosterone varies depending on animal age. In the samples from rams aged 2 and 3 years, there were no significant differences regarding the concentration of testosterone, the average for rams aged 2 years was 1. Instead, in samples from rams aged helminth immune evasion years have seen a sharp increase of testosterone, that reaching an averageconcentrationof9.

helminth immune evasion

Biosynthesis of this hormone occurs from cholesterol, in two ways: one is principally located in the Leydig cells of the testicles and a secondary route that takes place in adrenal.

Testosterone is the hormone responsible for the appearance of primary and secondary sexual characters and male sexual function.

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They can indirectly stimulate sperm maturation. Testosterone is critical for the expression of masculine sexual behaviors in mammals. Minimal concentrationsoftestosteronearerequiredforexpressionofheterosexualmatingbehaviorin male sheep [Roselli et al.

Pathogens that are present today have evolved following a long association with man and have developed unique strategies that have been optimized by natural selection to subvert the host immunity.

Testosterone secretion is correlated to external stimulants such as behavior of ewes, odor and estrous manifestation of ewes. Both sexual and pheromone production are dependent on the action of androgens [Kishk, ; Walkden Brown et helminth immune evasion.

A large variety of methods have been developed for determining concentrations of steroid hormones in biological samples. Biological tests and thinlayer chromatography were developed some time ago.


More recently, in vitro tests with cell lines sensitive to hormones and immunochemistry methods were used to determine concentrations of steroid hormones. Gas chromatography and gas chromatography coupled helminth immune evasion mass spectrometry methods were also used to detect low levels of hormones [Andrei et Lucrritiinificevol53seriaMedicinVeterinar al.

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In this study we followed, on the one hand, testing a gas chromatographic method for determining the concentration of testosterone in plasma collected from rams, and determining the relationship helminth immune evasion exists between this concentration andageoframs.

Samples of blood were collected from the jugular vein of rams, without anticoagulant, in order to separate the blood plasma.

Blood plasmawasthenanalyzedaccordingtothefollowingprotocol. Hormonesextraction: Extraction of hormones was performed in methanol, in several stages.

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Thus, 10ml blood plasma was added to 10 ml methanol and internal standards. Obtained suspension was maintained in an ice bath for 10 minutes and was added 10 ml distilled water. Was homogenized again, after which the samples were passed in a hot water bath at 60C helminth immune evasion 15 minutes.

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After cooling to room temperature, the mixture was centrifuge for 10 minutes at rpm. Separate liquid phase was treated, twice with hexane to remove lipids.

Aqueous methanol phase was then passed into a 50 ml vial and methanol removed by evaporation 45C using liquid concentrator Eppendorf Concentrator PLUS.

Aqueous extract thusobtainedwasfurtherseparatedandpurified.

helminth immune evasion

Purificationandderivatization: Column purification Varian C8SPE was conditioned previously with 2 ml methanol and 3 ml distilled water.

Aqueous extract was passed through helminth immune evasion column and hormones were elute with 2 ml of methanol, were collected in another tube, after which solvents were removed by evaporation at helminth immune evasion.

The derivatization reactions was performed directly into tubes which were collected extracts purified, by helminth immune evasion l mixture BSTFA bistrimethylsilyl trifluoroacetamide TMCS trimethylclorosilan in relative volumes of Samples helminth immune evasion kept for 2 hours at 60C.

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The solutions thus obtained were directly injected to gas chromatograph injectionvolumewas2 l. Prior injection, under the same conditions of analysis, of a mixture of standards has allowed us to identify the separated components by comparing the retention time.

In Figure 1, is shown helminth immune evasion obtained from separation of hormones in theplasmasamplecollectedfromrams. Retentiontimeoftestosteroneinplasmasampleswas For progesterone the retention time was Retention times are the same as those obtained when separating mixtures of standard solutions, progesterone and testosterone.