Fluorescein

Chemical synthesis

This substance was discovered by Adolphe von Bayer in 1871. The origin of the name would go back to 1878.

Biological functions

The pyoverdine is a biological Toxine, found in slightly different chemical forms, to which correspond of the cellular receivers (being able to accept various forms of pyoverdine). It could have several functions still badly included/understood.

The pyoverdines have a chemical affinity for the ferri-iron (ion Fe3+) higher than that of Sidérophore S produced by the mushrooms phytopathogenes, of which by the Fusarium (fusarinines), which confers on the microbes by producing an advantage competitive or adaptive, allowing them to become “antagonistic” other microbial groups able to collect this iron when its availability is limited by it.

By directed changes, researchers produced mutant bacteria ( P. syringae ) not producing a pyoverdine or not incorporating it. They showed that like the enzyme nitrate réductase , the pyoverdine is implied in rhizospheric but also telluric competence (capacity to exploit the ground as habitat) of P. syringae C 7R 12 (which has thanks to the nitrate réductase a competence Saprophyte enabling him to breathe in conditions of Anoxie). One in addition showed at the end of years 1990 that the pyoverdine produced by bacteria was a good Ligant which can complex other metals of which Actinide S, under certain conditions of pH (source: ). A test HPLC was developed with the Belgian CRA-W, which confirmed at more than 500 stocks of P. syringae the constancy of the produced pyoverdine ()

Uses:

Hydrogeology:

Its color being visible even with low dose, fluorescein is used to trace the underground escape, resurgence, rivers, etc

Waste water networks:

In the same way, fluorescein is used for the tests on the waste water networks, to find the advance of badly known networks, to identify the inversions between networks of waste water and rain, etc

Industrialist:

It makes it possible to detect the presence of escape on hydraulic systems (oil and fuel) complex, in particular on the machines with hydraulic fluid power (Vérin, connection…).

Medical field:

It is also used in certain drugs (e.g.: éosine), and in molecular biology as for the clothes industry of probes for PCR in real-time.
It was used in injection 20%, for the Angiographie S of the retina in fluorescence, but in June 2002, in France, the Afssaps imposed in agreement with the manufacturer the suspension of the AMM of this speciality and the withdrawal of all the batches of injectable solution of Sodic Fluorescéine FAURE on 20%, because of severe reactions of over-sensitiveness plus frequencies with fluorescein with 20% that with fluorescein with 10% (which remains authorized).
Au October 1st, 2004, 23 cases of serious undesirable effects were announced in France whose 5 case concluded by death from the patient was notified in France with AK-Fluor® which replaces Sodic Fluorescein Faure 10%, in stock shortage, because of difficulties of manufacture, according to the afssaps. The benign side effects are (isolated or associated):

- transitory nauseas and of the vomiting (frequent),

- Malayan and itchings, cutaneous eruption or urticaria generalized (more rarely).

More serious effects can sometimes follow these minor symptoms of allergy, in the minutes or hours following the injection:

- lowers Blood-pressure,

- edema of Quincke, respiratory symptoms (crisis of Asthme, respiratory distress);

and more rarely;

- sharp declines of blood-pressure, bringing a state of shock with possible heart failure

- turbid cardiac (cardiac arrest, Myocardial infarction; ex a Death by cardiac arrest according to the injection of 5 millilitres fluorescein with 5% for a angiography is described by newspaper JAMA in 1979)

- central nervous system disorders (convulsions, coma, cerebral vascular accident)

An inflammatory reaction and local pain can result from a diffusion of the product out of the vein during the injection The conjunctive ones, the skin and the urines are temporarily yellow fluorescent a few hours after the examination.

Molecular biology

Fluorescein is used as donor in the clothes industry of Sondes of PCR in real-time.

Navigation:

It is also used as means of easily transportable indication of help on boats of navigation. In the event of need, the spot formed by the product facilitates air detection largely, in particular for small boats (kayak of sea, etc)

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