Blood porphyrins

Herber RFM. 1980. Estimation of blood lead values from blood porphyrin and urinary delta-aminolevulinic acid levels in workers. Int Arch Occup Environ Health 45 169-179. 

In most porphyrias, excess metabolites can be detected in urine. Less polar porphyrins (i.e., coproporphyrins and protoporphyrin) are detectable in feces as they are excreted by the bile. The apolar protoporphyrin is eventually only detectable in blood. Porphyrins can easily be detected and measured by their intense fluorescence in mineral acids. The excitation wavelength is around 404 nm, and emission at about 615 nm. ALA is derivatized to a pyrrole and both, ALA and PBG, are detected by dimethylaminobenzaldehyde (DMAB), as described by Mauzerall and Granick [7]. 

The porphyrias. The human body does not use all of the porphobilinogen produced, and a small amount is normally excreted in the urine, principally as coproporpyrins (Fig. 16-5). In a number of hereditary and acquired conditions blood porphyrin levels are elevated and enhanced urinary excretion (porphy-... 

The metabolite methods include those for ALA, PEG, and urinary, fecal, plasma, and blood porphyrins. 

Topical application of ALA in amounts from 0.05 to 0.2 g cm (total 0.05 to 7.0 g ALA) does not lead to measurable systemic porphyrin levels in humans [53]. Therefore no systemic side effects are observed in topical ALA application techniques. However, in ALA-treated mice, liver, kidney, spleen and blood porphyrins also increased from basal levels, showing that ALA and/or ALA-induced porphyrins reach all tissues in this species even after topical application [20]. 

Aplastic anemia and leukemia are not the only health effects ascribed to benzene exposure. A number of recent studies have associated benzene exposure with chromosomal changes (aberrations) (118). Other studies have shown abnormalities in porphyrin metabolism and decrease in leucocyte alkaline phosphatase activity in apparendy healthy workers exposed to 10—20 ppm benzene (119,120). Increases in leukoagglutinins, as well as increases in blood fibrinolytic activity, have also been reported and are believed to be responsible for the persistent hemorrhages in chronic benzene poisoning (121,122). 

The synthesis of porphyrins from monopyrrolic, dipyrrolic, tripyrrolic and tctrapyrrolic precursors requires, even for an experienced porphyrin chemist, a substantial amount of time and effort to accomplish. As an alternative to these total synthetic routes, nature provides a source of prefabricated porphyrins. Among the several porphyrins which can be isolated from natural material,s the red blood pigment heme, protoporphyrin dimethyl ester81 b and hemato-porphyrin, both derived from heme, are the only compounds which can be obtained in sufficient amounts. Heme is available in almost unlimited amounts from slaughter-house waste. From 1 L of blood ca. 1 g of heme can be isolated.81 b Currently, heme is offered commercially by chemical retailers at a relatively low price so that is cheaper to buy hemin than to perform a self-isolation in the laboratory. 

The modification of porphyrins leading to isobacteriochlorins by C —C-bond formation is important to obtain a wide range of structurally different isobacteriochlorins which can then be further transformed. Protoporphyrin, deutoroporphyrin and hematoporphyrin (readily accessible from red blood pigment) are interesting and useful starting materials in the synthesis of isobacteriochlorins. 

High levels of lead can affect heme metabohsm by combining with SH groups in enzymes such as fer-rochelatase and ALA dehydratase. This affects porphyrin metabolism. Elevated levels of protoporphyrin are found in red blood cells, and elevated levels of ALA and of coproporphyrin are found in urine. 

There are large numbers of naturally occurring representatives, especially of pyrrole that include the important polypyrroles (porphyrins and corrins), and the nitropyrrole antibiotics such as pyr-rolomycins and pyrroxamycin. Derivatives of furan have been used as fungicides and A-vinylpyr-rolidone is an important monomer for the production of blood plasma extenders and for cosmetic applications. On account of the similarity in the pathways for the aerobic degradation of monocyclic furan, thiophene, and pyrrole, all of them are considered here. Anaerobic degradation of furans is discussed in Part 2 of this chapter. 

After this first step, where some samples are eliminated because they are not suited to the protocol, the positive ion mode is used to investigate haem, an iron porphyrin which is a blood marker. Spectra taken of the haem reference show that it can be detected due to [M]+ and [M+H]+ ions (respectively, at m/z 616.2 and 617.2), and also due to a large distribution of fragment peaks between m/z 350 and m/z 550 (Figure 15.12a). The same spectrum has also been obtained for haemoglobin leading to the conclusion that the presence of protein does not disturb the detection of haem. 

T. Malinski, F. Bailey, Z.G. Zhang, and M. Chopp, Nitric-oxide measured by a porphyrinic microsensor in rat-brain after transient middle cerebral-artery occlusion. J. Cereb. Blood Flow Metab. 13, 355-358 (1993). 

Anemia, elevation in erythrocyte porphyrin, kidney pathology residues (mg/kg fresh weight) of 603 in kidney, 501 in bone, 8 in liver, 2 in brain, 4.4 in blood, 0.8 in sciatic nerve, and 0.1 in crop... 

The photodynamic effect on red blood cells of the /xara-tetraglucosyl-porphyrin 31a and its analogous with the sugar unit in orto position has also been analysed. Considering the possibility of the photosensitiser causing hemolysis, this study became crucial.29 The two symmetric derivatives have proved to be ineffective in these cells. However, the asymmetric derivatives 49B and 50B are phototoxic and changes in hematological parameters were observed.29... 

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