Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PIGMENTATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2006

Aging effect on the pigment composition and color of Vitis vinifera L. Cv. Tannat wines. Contribution of the main pigment families to wine color.

Red wines made from Vitis vinifera L. cv. Tannat grapes are known to possess high contents of tannins and intense color, features that are responsible for the originality of these wines. This work aimed to study the evolution of the pigment composition and CIELAB color parameters as Tannat wines become older, as well as to establish the contribution to wine color of the main pigment families. Tannat wines produced in Uruguay from grapes of the same vineyard in six consecutive vintages (1998-2003) and Tannat grapes of the 2003 harvest were analyzed by means of HPLC-DAD-MS and UV-vis spectrometric techniques. The correlations between the different pigment families and the CIELAB parameters revealed the importance of the variations of the percentage, found in anthocyanins and flavanol-anthocyanin acetaldehyde-mediated condensation products (decrease) and pyranoanthocyanins and direct condensation products (increase), in the modification of the color from purple-red hues to more orange-red ones. The color suffered qualitative rather than quantitative changes, that is, the hue (h*ab) increased, whereas the chroma (C*ab) and lightness (L) did not show a defined trend with time.

Chromatography, High Pressure Liquid↗
PubMed2001

Influence of source and ratio of xanthophyll pigments on broiler chicken pigmentation and performance.

One experiment was conducted using 960 1-d-old, sexed broilers of Ross 308 strain from 1 to 43 d to evaluate if one type of chemically isomerized marigold with 25% of xanthophylls as zeaxanthin (SME-25) could produce pigmentation equivalent to the current addition of conventional marigold with 10% of xanthophylls as zeaxanthin (SME-10) plus canthaxanthin (CTX) in practical broiler diets (maize-wheat-soybean). Birds were allocated in 32 pens, in a randomized complete block design (four blocks x four treatments). The treatments consisted of a nonpigmented control (T1), a combination of 35 ppm of yellow xanthophylls (YX) from SME-10 + 5 ppm of CTX (T2), a combination of 32 ppm of YX from SME-10 + 2 ppm of CTX (T4), and one treatment with 40 ppm of YX from a new SME-25 (T3). There were no significant treatment effects on chicken performance. All color parameters (Minolta coordinates, Roche color fan scores, Rank test) presented significant differences (P < 0.0001) because of dietary pigments on shanks and breast skin. Birds fed the SME-25 diet had less pigmentation than those fed equivalent quantities of a combination of SME-10 + CTX. The Minolta coordinate "b" measured in breast skin was a good indicator of YX content in feed, whereas the "a" coordinate measured on the shank showed a linear relationship with the dietary CTX level (r = 0.61, P < 0.0001). The same visual color classification of chickens was achieved irrespective of the rank test performed (by shank or carcass color). Lutein and zeaxanthin from the SME-25 product had lower deposition rates in skin and fat tissues than those from the SME-10 product. This finding seems to be related to the ratio of zeaxanthin stereoisomer RR (optically active) vs. RS that was found in tissues from the SME-10 product (97.8%:2.2%), whereas with SME-25 this ratio was 16.0:84.0%. These results suggest that inclusion of only the SME-25 product could not replace the current addition of SME-10 and CTX combinations.

Animal Feed↗
PubMed1989

Proliferating giant pigmented nevus: a report of an unusual tumor occurring in association with a congenital giant pigmented nevus.

A 32-year-old Japanese woman with a giant pigmented congenital nevus of the torso presented with a massive pigmented tumor mass of the vulva which grew over an 8-year period. Histologically, the tumor was composed of benign appearing nevus-like cells with focal areas of extensive fibrous response. The tumor cells were positive for S-100 protein and with an antihuman melanoma antibody (MoAb 225, 28S) stain. Electron microscopy confirmed the nevomelanocytic nature of the tumor cells and demonstrated peculiar cytoplasmic crystalline tubular structures similar to those seen in cells infected with herpes virus type II. We propose the term "proliferating giant pigmented nevus" for this previous undescribed tumor.

Adult↗
PubMed1991

Pigments and ultrastructures of pigment cells in xanthic sailfin mollies (Poecilia latipinna).

Electron micrographs of skin from xanthic (gold) sailfin mollies revealed numerous xanthophores, as well as scattered melanophores. The melanophores were seen to contain premelanosomes in various stages of development. This is consistent with the fact that xanthic mollies have been shown to be tyrosinase positive. Melanosomes in xanthic mollies appear to develop by one of two pathways: 1) from an endoplasmic reticulum-derived vesicle which develops an internal lamellar framework, and 2) by fusion of multiple Golgi-derived vesicles which lack an internal lamellar framework. Analysis of the pigments in the skin of the xanthic mollies identified four colorless pteridine pigments (xanthopterin, isoxanthopterin, neopterin, and pterin) and a carotenoid with an absorbance spectrum similar to beta-carotene. It appears that, unlike some other poeciliid fishes, sailfin mollies do not use pteridine pigments for orange coloration. Rather, they appear to rely primarily on carotenoids.

Animals↗
PubMed1988

Familial grouped pigmentation of the retinal pigment epithelium.

Grouped pigmentation of the retinal pigment epithelium was found in a father and his son. They had a normal resting potential on the electro-oculogram, but the son had a lower normal light rise. We believe this is the first description of familial grouped pigmentation.

Child↗
PubMed1999

Fatty acid profiles in pigmented and non-pigmented strains of S. marcescens.

Wild, pigmented strains of Serratia marcescens and their non-pigmented mutants were compared on the basis of fatty acid profiles and lipid content. Classic biochemical tests show only minor differences, as well as fatty acid ratio C18:C16. The total amount of lipid synthesized and the saturated/unsaturated fatty acids ratio disclose a sharp total lipid reduction and a high percentage of unsaturated fatty acids in the pigmented strains, placing them in separated clusters compared with the nonpigmented mutants. It is hypothesized that the synthesis of the polyacetate required for the completion of the prodigiosin molecule may result in waste of methyl groups and thus affect the total amount of lipids.

Chromatography, Gas↗
PubMed1992

[Krypton laser therapy. Use in secondary serous detachment of the retinal pigment epithelium and in multiple idiopathic serous detachments of the retinal pigment epithelium].

Two variants of serious detachments of the retinal pigment epithelium (RPE) are demonstrated with reports of typical cases: (1) secondary serous detachment of the RPE; (2) idiopathic serous detachment of the RPE (pigment epithelium detachment not associated with any other retinal or choroidal disease). Fluorescein angiographic criteria for differential diagnosis and the resulting different techniques of krypton laser coagulation are portrayed: (a) focal krypton laser coagulation of the total area of the pigment epithelium detachment; (b) circular, one-row laser coagulation at the detachment borders. The advantages of circular, one-row laser coagulation of idiopathic serous RPE detachment over coagulation of the total area of the RPE detachment are described: first, these are fewer scotomas following coagulation; second, fewer laser foci are required; and third, the risk of subretinal bleeding is lower. These findings emphasize the efficiency of circular, one-row laser coagulation at the detachment borders in the treatment of idiopathic serous RPE detachments.

Adult↗
PubMed1992

Polyethylene-glycol-mediated delivery of liposome-entrapped pigments into fibroblasts: experimental pigment cells as models for mutator phenotypes.

The role of epidermal melanin pigments in the development of skin cancer remains unclear. A new technique for the specific introduction of compartmentalized melanin into nonpigmented human fibroblasts through the use of liposomes and polyethylene glycol (PEG) is presented. The delivery of liposome-encapsulated material to cells was characterized by: (a) high efficiency of delivery through PEG-mediated endocytosis at 37 degrees C; (b) intracellular acidification of liposome entrapped pH-sensitive 8-hydroxypyrene-3,6,8-trisulfonic acid after delivery; (c) similar incorporation and acidification of apolipoprotein E-associated liposomes into fibroblasts via the low-density lipoprotein-receptor pathway; and (d) discharge into the extracellular space after incorporation. Similar experiments were carried out with melanin-containing liposomes that were used to introduce compartmentalized melanin into fibroblasts, through PEG-mediated delivery. These "artificial" melanocytes had functional analogies to genuine melanocytes in that (a) in both cell types melanin compartmentalization was at a lower pH; and (b) liposome contents were later expelled in analogy to the putative biological process of melanin expulsion from the melanocyte. The modified fibroblasts provided potential "mutator" phenotypes with specific melanin pigmentation, and established a new basis for studying the role of melanin pigmentation in cancer development.

Cell Compartmentation↗
PubMed2003

[A comparison of the mRNA expression of VEGF and its receptor FLK-1 in rabbit iris pigment epithelium cells and retinal pigment epithelial cells].

OBJECTIVE: To investigate mRNA expression of vascular endothelial growth factor (VEGF) and its receptor FLK-l in iris pigment epithelium (IPE) cells and retinal pigment epithelium (RPE) cells, and the feasibility of transplantation of autologous IPE cells to substitute RPE in the treatment of age-related macular degeneration (AKMD) and diseases of RPE dysfunction. METHODS: IPE and RPE cells were isolated from pigmented rabbits. The expression of mRNA for VEGF and FLK-l were detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Rabbit IPE and RPE cells express VEGF mRNA and FLK-l; the express of VEGF and FLK-1 mRNA in IPE cells was relatively low compared with the expression in RPE cells. The amount of VEGF mRNA in IPE cells was 44.62% of RPE cells, and amount of FLK-l mRNA was 52.36% of RPE cells- The results of the differences of expression of VEGF and FLK-l mRNA between IPE and RPE cells was statistically significant (t-test, P < 0.001). CONCLUSIONS: VEGF and FLK-l mRNA in IPE cells express is relatively low compared with the expression in RPE cells, and the results suggest that IPE cells could be more beneficial than RPE cells in the transplantation into the subretinal space.

Animals↗
PubMedDate not supplied

[Differentiation of the retina and pigment epithelium in the ontogeny of the common frog. 2. Pigment epithelium].

Changes in the differentiating pigment epithelium cells have been studied in Rana temporaria by transmission electron microscopy. Ultrastructural features of the pigment epithelium functions at successive developmental stages have been established: the phagocytic function appears the first (judging by utilization of embryonic pigment from the primary eye cavity), it is followed by the transport and barrier functions (as the secondary eye cavity and vascular envelope develop), while phagocytosis related to the process of renovation of the external segments of photoreceptors and the function of screening appear later.

Animals↗
PubMedDate not supplied

Characterization and tumorigenicity of spheroids composed of pigmented or non pigmented B16 melanoma cells.

A parental line of mouse B16 melanoma cells (B16) and two derived cloned lines, either pigmented (B16P) or non pigmented (B16NP), were cultured in vitro as spheroids. After 48 hrs, the pigmented cells (B16, B16P) formed smaller and looser aggregates, with higher rates of cell proliferation and lower amounts of extracellular matrix as compared to B16NP spheroids. The three lines were more tumorigenic when inoculated subcutaneously as spheroids than as isolated cells. Furthermore, B16P or B16 spheroids developed richly vascularized subcutaneous tumors and metastases more rapidly than B16NP aggregates. After intravenous injection of spheroids, the measurement with an image analyzer of the area of sections in lung colonies indicated that B16P colonies were larger and more numerous than those induced by B16NP cells.

Animals↗
PubMed1997

[The development of the pigment epithelium and its interrelation with uveal pigment cells].

Authors propose one study of retinal cells population in different stages of ontogenesis and one study of the pigmentogenesis process at the level of uveal tract and external retinal stratum. The study was achieved with embryonic and fetal technique of paraffin inclusion. Concomitantly with loading with pigment of the external retinal stratum and so pigmentary uveal tract is present. Dynamics of the retinol cells population varies with stages and chronological age, the number of pigmented uveal cells increasing proportionally but at different parameters with the pigmented retinal stratum one simultaneous with age under influence specially of humoral factors.

Gestational Age↗
PubMed2001

Erratum: DNA damage in isolated rat hepatocytes exposed to C.I. pigment orange 5 and C.I. pigment yellow 12 by the alkaline comet assay; peter moller, Hakan wallin, niels grunnet, lotte risom, and lisbeth E. Knudsen; teratogenesis, carcinogenesis, and mutagenesis 18: 9-16 (1998)

To the Editor: In the third sentence of the Result section we have written wrong SDs for the two pigments. The correct sentence should be: C.I. pigment orange 5 produced a statistically significant increase in TM at 5 &mgr;g/ml (mean 1.66, SD 0.54) and C.I. pigment yellow 12 at 20 &mgr;g/ml (mean 1.49, SD 0.61). These SD correspond to the SEM values outlined in Figures 2 and 3, and were the SD that the statistics refer to.

Journal Article↗
PubMed2004

Ectopic deposition of melanin pigments as detoxifying mechanism: a paradigm for basal nuclei pigmentation.

Melanins are UV shielding pigments found in skin and other light exposed tissues. However, a kind of melanin, named neuromelanin (NM), is found in those deep brain loci that degenerate in Parkinson's disease (PD), where no such a function may be imagined. The NM synthetic pathway, different from the one of eumelanin based on tyrosinase, is still obscure as well as its physiological function. Here we show that under conditions of excess of toxic quinone concentration, nonmelanocytic cell strains (i.e., primary keratinocytes) may accumulate a dark cytoplasmatic pigment that proved to be a melanin. The ability of pigment deposition, possibly driven by peroxidases, is restricted to diploid cells and increases cell survival acting as a sink for potentially hazardous quinones. We suggest that in the basal nuclei, exposed to high level of catecholaminergic neurotransmitters, NM deposition is a relevant antioxidant mechanism by trapping quinones and semiquinones, thus protecting neurons from accumulating damage over many years. In this perspective, just as a hypothesis, we may imagine that PD neuron degeneration is the consequence of a reduced/abrogated ability to produce neuromelanin.

Antioxidants↗
PubMed2000

Abnormal pigmentation of schwannoma attributed to excess production of neuromelanin-like pigment.

Five cases of non-melanotic pigmented schwannoma with excess accumulation of neuromelanin are presented. The tumors were composed basically of spindle or fusiform tumor cells, compatible with those of classical schwannoma, together with varying numbers of tumor cells containing various amounts of light brown or grayish pigment. Fontana-Masson stain demonstrated argentaffin granules in some tumor cells of each tumor and bleaching with potassium permanganate abolished argentaffin reaction. Ultrastructural examination demonstrated the granules contained fine particles with heterogeneous density, occasionally together with coarse granular materials or amorphous high-density areas, indicating lysosome or autophagosome. Neither typical melanosomes nor neurosecretory granules were detected. In immunohistochemistry, neurogenic markers as well as CD68 were expressed in most tumor cells in each case and various numbers of tumor cells were positive for Leu7 and CD34. Lysozyme was also frequently positive in tumor cells, especially in granular cells. HMB45 was not expressed in any of the cases. These findings indicate that these cases are schwannomas with abnormal accumulation of neuromelanin-like pigment.

Aged↗
PubMedDate not supplied

Epidermolysis bullosa simplex herpetiformis of Dowling-Meara with mottled pigmentation: the relationship between EBS herpetiformis and EBS with mottled pigmentation.

A 6-year-old girl with epidermolysis bullosa simplex (EBS) is described. Clinical features include generalized herpetiform blistering of the skin, healing without scars, intraoral blistering, nail dystrophy, palmoplantar keratoderma, and improvement with age. An unusual feature was the presence of a striking mottled pigmentation involving the arms, trunk, and legs. Histology, immunofluorescence, and electron microscopy of a fresh lesion showed an intraepidermal split within the basal keratinocytes, focal hyperpigmentation of the basal cells without an inflammatory infiltrate, and tonofilament clumping. Our patient illustrates the clinical features of Dowling-Meara EBS with the pigmentary changes of EBS with mottled pigmentation. The relationship between EBS of Dowling-Meara and EBS with mottled pigmentation is discussed.

Aging↗
PubMed1998

Processing of defensive pigment in Aplysia californica: acquisition, modification and mobilization of the red algal pigment, r-phycoerythrin by the digestive gland.

The marine snail Aplysia californica obtains its purple defensive ink exclusively from the accessory photosynthetic pigment r-phycoerythrin, which is found in the red seaweeds of its diet. The rhodoplast digestive cell, one of three types of cell lining the tubules of the digestive gland, appears to be the site of catabolism of red algal chloroplasts (rhodoplasts) since thylakoid membranes, including phycobilisome-sized membrane-associated particles, were found within the large digestive vacuoles of this cell. Immunogold localization showed that there was a statistically significant occurrence of the red algal phycobilisome pigment r-phycoerythrin within these rhodoplast digestive vacuoles, but not in other compartments of this cell type (endoplasmic reticulum, mitochondria, nucleus) or in other tissues (abdominal ganglion). Immunogold analysis also suggested that the rhodoplast vacuole is the site for additional modification of r-phycoerythrin, which makes it non-antigenic: the chromophore is either cleaved from its biliprotein or the biliprotein is otherwise modified. The hemolymph had spectrographic absorption maxima typical of the protein-free chromophore (phycoerythrobilin) and/or r-phycoerythrin, but only when the animal had been feeding on red algae. Rhodoplast digestive cells and their vacuoles were not induced by the type of food in the diet: snails fed green seaweed and animals fed lettuce had characteristic rhodoplast cells but without the large membranous inclusions (rhodoplasts) or phycobilisome-like granules found in animals fed red seaweed. Two additional cell types lining the tubules of the digestive gland were characterized ultrastructurally: (1) a club-shaped digestive cell filled with electron-dense material, and (2) a triangular 'secretory' cell devoid of storage material and calcium carbonate. The following model is consistent with our observations: red algal rhodoplasts are freed from algal cells in the foregut and then engulfed by rhodoplast digestive cells in the tubules of the digestive diverticula, where they are digested in membrane-bound vacuoles; r-phycoerythrin is released from phycobilisomes on the rhodoplast thylakoids and chemically modified before leaving the digestive vacuole and accumulating in the hemolymph; the pigment then circulates throughout the body and is concentrated in specialized cells and vesicles of the ink gland, where it is stored until secreted in response to certain predators.

Journal Article↗
PubMed2001

Pigment epithelium-derived factor supports normal Müller cell development and glutamine synthetase expression after removal of the retinal pigment epithelium.

In conditions in which the retinal pigment epithelium (RPE) is dystrophic, carries a genetic mutation, or is removed physically, Müller cells undergo degenerative changes that contribute to the retinal pathology. We previously demonstrated that pigment epithelium-derived factor (PEDF), a glycoprotein secreted by the RPE cells with neuroprotective and differentiation properties, protects against photoreceptor degeneration induced by RPE removal. The purpose of the present study was to analyze the putative gliosupportive activity of PEDF on Müller cells of RPE-deprived retinas and assess whether protection of Müller cells was correlated with improved photoreceptor outer segment assembly. Eyes were dissected from Xenopus laevis tadpoles, and the RPE was removed before culturing in medium containing purified PEDF, PEDF plus anti-PEDF, or medium alone. Control eyes matured with an adherent RPE or in medium containing PEDF plus nonimmune serum. Müller cell ultrastructure was examined. Glial fibrillary acidic protein (GFAP) and glutamine synthetase were localized immunocytochemically, and the corresponding protein levels were quantified. In control retinas, Müller cells were structurally intact and formed adherens junctions with neighboring photoreceptors. In addition, they did not express GFAP, whereas glutamine synthetase expression was high. RPE removal dramatically altered the ultrastructure and biosynthetic activity of Müller cells; Müller cells failed to form adherens junctions with photoreceptors and glutamine synthetase expression was suppressed. PEDF prevented the degenerative glial response; Müller cells were ultrastructurally normal and formed junctional complexes with photoreceptors. PEDF also preserved the expression of glutamine synthetase at near-normal levels. The morphogenetic effects of PEDF were blocked by the anti-PEDF antibody. Our study documents the glioprotective effects of PEDF and suggests that maintenance of the proper Müller cell ultrastructure and expression of glutamine synthetase may be necessary to support the proper assembly of photoreceptor outer segments.

Animals↗