Affinity of putrescine, spermidine and spermine for pigmented tissues

Toxicological hair analysis: Pre-analytical, analytical and interpretive aspects

Background and aims Hair analysis for drug detection is one of the widely accepted imperative techniques in the field of forensic toxicology. The current study was designed to investigate the efficacy of chromatography for detection of drugs of abuse in hair. Method A comprehensive review of articles from last two decades on hair analyses via PubMed and similar resources was performed. Issues concerning collection, decontamination and analytical techniques are summarised. Physiochemical nature of hair, mechanism of drug incorporation and its stability in hair are briefly discussed. Furthermore, various factors affecting results and interpretation are elucidated. Result A hair sample is chosen over traditional biological samples such blood, urine, saliva or tissues due to its inimitable ability to provide a longer time frame for drug detection. Its collection is almost non-invasive, less cumbersome and does not involve any specialised training/expertise. Recent advances in analytical technology have resulted in better sensitivity, reproducibility and accuracy, thus providing a new arena of scientific understanding and test interpretation. Conclusion Though recent studies have yielded many insights into drug binding and drug incorporation in hair, the major challenge in hair analysis lies in the interpretation of results, which may be affected by external contamination and thus lead to false-positives. Therefore, there is a need for more sensitive and selective analysis methods to be developed in order to minimise factors that induce the effect of melanin, age and so on, and this would certainly provide a new dimension to hair analysis and its applications.

Polyamines and hair: a couple in search of perfection

Polyamines (spermidine, putrescine and spermine) are multifunctional cationic amines that are indispensable for cellular proliferation; of key significance in the growth of rapidly regenerating tissues and tumors. Given that the hair follicle (HF) is one of the most highly proliferative organs in mammalian biology, it is not surprising that polyamines are crucial to HF growth. Indeed, growing (anagen) HFs show the highest activity of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis, while inhibition of ODC, using eflornithine, results in a decreased rate of excessive facial hair growth in vivo and inhibits human scalp hair growth in organ culture. In sheep, manipulation of dietary intake of polyamines also results in altered wool growth. Polyamine-containing nutraceuticals have therefore been proposed as promoters of human hair growth. Recent progress in polyamine research, coupled with renewed interest in the role of polyamines in skin biology, encourages one to revisit their potential roles in HF biology and highlights the need for a systematic evaluation of their mechanisms of action and clinical applications in the treatment of hair disorders. The present viewpoint essay outlines the key frontiers in polyamine-related hair research and defines the major open questions. Moreover, it argues that a renaissance in polyamine research in hair biology, well beyond the inhibition of ODC activity in hirsutism therapy, is important for the development of novel therapeutic strategies for the manipulation of human hair growth. Such targets could include the manipulation of polyamine biosynthesis and the topical administration of selected polyamines, such as spermidine.

Polyamine-Substituted Gadolinium Chelates: A New Class of Intracellular Contrast Agents for Magnetic Resonance Imaging of Tumors

A new class of intracellular contrast agents (CA) for magnetic resonance imaging has been developed, based on Gd(DTPA) with two positively charged amide-linked substituents. Uptake of Gd(DTPA) into cultured tumor cell lines (B16 mouse melanoma, MH3924A Morris hepatoma) was below the detection limit while CA with the melanin-binding pharmacophore 2-(diethylamino)ethylamine reached intracellular concentrations of ca. 0.03 fmol/cell (ca. 20 microM) for melanoma and 0.02 fmol/cell for hepatoma (24 h at 10 microM CA). With the polyamine substituents bis(2-aminoethyl)amine or spermidine, CA uptake increased up to 3-fold for melanoma (0.083 fmol/cell) and 9-fold for hepatoma (0.18 fmol/cell). Uptake of polyamine-substituted CA was reduced by the polyamine transport inhibitor benzyl viologen. Molar relaxivities for three Gd-DTPA-polyamine complexes were in the range 5.6-6.9 for the free complex in solution and 7.7-23.5 s-1 mM-1 for Morris hepatoma cell pellets. T1-weighted magnetic resonance imaging at 2.35 T of rats with MH3924A tumors showed contrast enhancement in tumor at 1 and 24 h postinjection of polyamine-substituted CA.

Oxidative degradation of polyamines in rat pancreatic hypertrophy

In the hypertrophic pancreas, we studied the oxidative degradation of polyamines, which are endogenous polycations important for cell division, growth and differentiation. To induce pancreatic hypertrophy, rats were fed on a semi-synthetic diet containing a daily dose of 42 mg phytohaemagglutinin per rat for 5 or 10 days. In the model, the activities of polyamine oxidase (the enzyme that degrades spermidine, spermine and mainly their acetyl derivatives) and diamine oxidase (the key enzyme of terminal catabolism of polyamines in vivo) increased by 100-180% and 90-100%, respectively, parallel to an elevation in polyamine content (40-100%). The results suggest that in pancreas hypertrophy, which does not exhibit stimulation of spermidine/spermine N1-acetyltransferase activity, increases in the activity of polyamine and diamine oxidases are related events that lead to putrescine formation and removal of excess polyamines.

Antimelanoma activity of chloroquine, an antimalarial agent with high affinity for melanin

The antimalarial agent chloroquine is known for high affinity for melanin. This 4-aminoquinoline derivative was examined for anti-melanoma activity and uptake into melanoma cells. Chloroquine inhibited growth of cultured melanoma cells; the effect was much greater to a moderately pigmented cell line HMV-II than to a nonpigmented HMV-I. Treatment with chloroquine at a dose of 62 mg/kg i.p. for 12 days prolonged by 71% the life span of mice bearing B16 melanoma, while 24-day treatment at 31 mg/kg resulted in a 81% increase in life span. HMV-II cells showed a two-fold increase in uptake of chloroquine as compared with HMV-I cells. Chloroquine, 24 hr after administration to mice implanted s.c. with B16 melanoma, was selectively accumulated in the pigmented tissues, melanoma and eyes. Other nonpigmented tissues such as the liver, lung, and kidney showed rapid uptake (within 1 hr) and release. These results suggest that chloroquine is toxic to pigmented melanoma cells, the process being partly mediated by binding to melanin.

Mechanism of growth inhibition of melanoma cells by 4-S-cysteaminylphenol and its analogues

Our previous studies have shown that 4-S-cysteaminylphenol (4-S-CAP) causes a significant inhibition of in vivo melanoma growth and a marked depigmentation of black skin and hair follicles. These studies have suggested a role of tyrosinase in the manifestation of these in vivo effects. In this study 4-S-CAP and its analogues were examined for their effects on the growth of human melanoma cells in vitro. 4-S-CAP and 4-S-HomoCAP exhibited strong cytotoxicity with effects much greater than those of alpha-methyl-4-S-CAP and N,N-dimethyl-4-S-CAP. The cytotoxicity of the former two amines was completely prevented by semicarbazide, an inhibitor of plasma monoamine oxidase, while that of the latter two was not prevented by semicarbazide, catalase, and phenylthiourea, a tyrosinase inhibitor. In culture medium 4-S-CAP was rapidly converted by the action of monoamine oxidase present in fetal bovine serum to the aldehyde which was then metabolized to the alcohol and the carboxylic acid when cells were present. alpha-Methyl-4-S-CAP was found to exert higher cytotoxicity to cells with higher tyrosinase activity and melanin content. These results suggest that the in vitro cytotoxicity of 4-S-CAP and 4-S-HomoCAP is mediated through conversion to the aldehydes while that of alpha-methyl-4-S-CAP appears to be dependent on tyrosinase activity to some extent.

The effects of various nutritional supplements on the growth, migration and differentiation of Xenopus laevis neural crest cells in vitro

This study investigates the nutritional requirements of Xenopus laevis neural crest cells and melanophores developing in vitro. A comparison is made between the growth and differentiation of cells in serum-containing medium and a chemically defined, serum-free medium that we have designed. Our chemically defined medium is more efficient than serum-supplemented medium in promoting proliferation of these cells. Several supplements are required to enhance culture development. These include insulin, alpha-melanocyte stimulating hormone, somatotropin, luteotrophic hormone, linoleic acid, uridine, and putrescine. In addition, collagen and fibronectin provide the most conducive environment tested for cell migration and adhesion.

Polyamine uptake by bovine adrenocortical cells

Bovine adrenocortical cells of fasciculo-reticulata origin in primary culture actively accumulate polyamines from the extracellular medium in an energy-dependent process. At low extracellular concentration (e.g., 1 microM putrescine), the transport system resulted in a several-hundred-fold concentration of polyamine in the cellular compartment within 1-2 h of incubation. Putrescine uptake appeared to be the sum of a sodium-dependent, saturable process, with an apparent Km of about 10 microM and of a non-saturable, sodium-independent component. By contrast, spermine was taken up by the cells mostly in a sodium-independent manner. Cross-competition experiments suggested that both polyamines were at least partly transported by the same system. Using specific corresponding probes, it was shown that the polyamine uptake was independent of the amino acid transport systems of the A, L and N types known in a number of cell systems. Adrenocortical cell polyamine content is known to be modulated by adrenocorticotropin through induction of ornithine decarboxylase activity. The existence of a specific uptake system in these cells opens the possibility of a more rapid pathway for the regulation of cellular polyamine levels. It remains to be examined whether this polyamine transport system is under hormonal control, and whether this can support the suggestion that polyamines may represent a form of intracellular messengers in the mechanism of hormone action.