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PubMed1996

Incorporation of codeine and metabolites into hair. Role of pigmentation.

Xenobiotics circulating in the blood may become incorporated into growing hair. Melanin has affinity for many pharmacologically unrelated drugs and is responsible for the pigmentation in hair. To assess the role of pigmentation in the incorporation of drugs into hair, the distribution of codeine and its metabolites was studied in Sprague-Dawley (SD; white nonpigmented hair), Dark Agouti (DA; brown pigmented hair), and hooded Long-Evans (LE; both black pigmented and white nonpigmented hair) rats. Codeine was administered at a dose of 40 mg/kg/day i.p. for 5 days. Fourteen days after beginning the dosing protocol, hair was collected and analyzed for codeine, and its metabolite, morphine, by positive-ion chemical ionization GC/ion-trap MS. The plasma pharmacokinetics for codeine and morphine were also determined after a single 40 mg/kg injection (equivalent to first dose in 5-day dosing protocol) in all three strains of rats. Hair and plasma codeine and morphine concentrations were also determined after acid hydrolysis to evaluate the presence of glucuronide metabolites. Codeine concentrations in the hair of SD, DA, and pigmented LE hair were 0.98 +/- 0.10, 5.99 +/- 1.24, and 111.93 +/- 18.69 ng/mg hair, respectively; morphine concentrations were 0.34 +/- 0.04, 0.51 +/- 0.11, and 14.46 +/- 1.81 ng/mg hair, respectively; morphine glucuronide concentrations were 0.67 +/- 0.08, 1.04 +/- 0.37, and 13.80 +/- 3.60 ng/mg hair, respectively. Studies examining the in vitro binding of [3H] codeine and [3H]morphine to hair demonstrated both specific and nonspecific binding sites for codeine and morphine. Pigmented hair from LE rats possessed the greatest number of binding sites, white hair from SD rats contained the least, and brown hair from DA rats was intermediate. A time course study of codeine and its metabolites showed pigment-mediated differences in incorporation of codeine and metabolites within a few hours of drug administration. These data indicate that pigmented hair possesses a greater capacity to bind and incorporate codeine and its metabolites than does nonpigmented hair. Interpretation of hair concentrations of drugs should involve consideration of hair pigmentation.

Animals↗
PubMed1996

Increased pigmentation in scleroderma.

OBJECTIVE: Increased pigmentation is found in patients with scleroderma (systemic sclerosis, SSc) even in areas that have never clinically been involved with skin thickening. We wanted to determine if the pigmentation is due to subclinical sclerodermatous changes, or a systemic factor such as an increase in adrenocorticotropic hormone (ACTH). METHODS: To determine if clinically uninvolved skin that is pigmented differs from nonpigmented skin, skin biopsies were taken from patients with scleroderma from 2 different sites: (1) from pigmented but otherwise clinically normal skin, and (2) from nonpigmented clinically normal skin adjacent to the first site. Biopsies were examined by a dermatopathologist for evidence of dermal and epidermal changes. Cosyntropin stimulation tests were performed after baseline cortisol and ACTH samples were obtained. RESULTS: Six patients with diffuse SSc (dSSc) and 4 with limited SSc (ISSc) had skin biopsies. Patients with dSSc were more likely than those with ISSc to have increased pigmentation in uninvolved skin. Pigmented skin specimens had either a higher content of epidermal melanin and/or a more severe degree of pigmentary incontinence with a higher number of dermal melanophages in the superficial dermis. The cosyntropin stimulation tests were normal and there were no differences between subjects with diffuse and limited SSc or between those with and without increases in pigmentation. CONCLUSION: Clinically uninvolved skin in many of these patients with SSc was abnormal, and subtle changes of SSc were present, especially in the pigmented biopsies. There was no evidence of adrenal deficiency in these patients. It is difficult pathologically to differentiate the changes in pigmented compared to unpigmented skin in patients with SSc, except for changes of increased melanin and pigmentary incontinence.

Adrenocorticotropic Hormone↗
PubMed1976

[Influence of some nutritional factors on the canthaxanthine pigmentation of the rainbow trout].

The present investigation was made to approve nutritionnal factors which affect the utilisation of food canthaxanthin by hatchery trout. Rainbow trout were obtained from a commercial trout farm, kept in running water and feeding in experimental pellets for 4 to 8 weeks. Five diets were tested (1-standard [7.5 u.i/g], 2-low protein content, 3-High lipid content, 4-non supplemented with vitamin A, 5-High vitamin A content [23 U.I./g]). All diets containing 250 mg of canthaxanthin per kilo of food, the fish were fed at the rate of approximately 2.5 p. 100 of their body weight per day. The estimation of canthaxanthin from fish tissues was accomplished as follows: the tissues were gomogeneized and extracted with several volumes of solvents. The solution containing all the pigment was evaporated. The purification of the canthaxanthin was obtained by column silica gel chromatography. The pigment was eluated with ethyl-ether as solvent. Quantitative assay of total carotenoïd was effected by spectre photometric estimation of optical density at 480 nm of this fraction dissolved in benzene. The carotenoïd composition of this fraction was studied by silica-gel thin layer chromatography. In these conditions:--it was shown by spectral studies that the canthaxanthins present in the diet are essentially those deposed in the flesh of the trout fed;--a series of experiment were made to examine the effect of composition of artificially composed feeds for pigmentation of the rainbow trout. The pigment deposition was found to correlate with the amount of lipids present in these diet. In this condition, the pigment is more dispersed with lipids present and the pigment absorption may be facilitated and later be deposed. 8 weeks alimentation are needed to observe the effect of these nutritionnal factor;--when the diet is non supplemented with vitamin A, the same quantity of canthaxanthin mixed with this food gives trout redder flesh than the standard diet. On an other hand, an antagonist effect of diet with high vitamin A content is demonstrated on the amount of the pigment deposed in the flesh of trout;--no effect of protein content of the diet was found in these experiments;--no effect of ratio calorie/protein of the diets with the intensity of deposed pigment in the flesh rainbow trout;--a correlation between neutral lipids of the tissue and the pigment deposed in the flesh of the trout fed with canthaxanthin was confirmed.

Animal Nutritional Physiological Phenomena↗
PubMed1956

A new photosensitive pigment of the euryhaline teleost, Gillichthys mirabilis.

Retinal extracts have been prepared from dark-adapted mudsuckers by treatment of retinal tissue or of isolated outer segments of the visual cells with digitonin solution. The extracts were examined spectrophotometrically and found to absorb light maximally between the wave lengths of 488 and 510 mmicro, depending on the proportion of yellow impurities and light-sensitive pigment present. This photosensitive pigment was shown to be homogeneous by partial bleaching of the extracts with monochromatic light of various wave lengths from 390 to 660 mmicro. The mudsucker pigment was specifically demonstrated not to be a mixture of rhodopsin and porphyropsin; the adequacy of the method used to analyze such mixtures was shown by performing a control experiment with an artificial mixture of bullfrog rhodopsin and carp porphyropsin. Comparison of the hydroxylamine difference spectrum and of the absorption maximum of the purest retinal extract located the mudsucker photosensitive pigment maximum at 512 +/- 1 mmicro. Extraction of retinal tissue with a fat solvent after exposure to white light gave a preparation which after the addition of antimony chloride reagent developed the absorption band maximal near 664 mmicro, which is characteristic of retinene(1). If an hour intervened between exposure of the retinal tissue to light and extraction of the carotenoid, the antimony trichloride test gave a color band maximal at 620 mmicro, characteristic of vitamin A(1). No evidence of retinene(2) or vitamin A(2) was obtained. The euryhaline mudsucker has, therefore, a photosensitive retinal pigment with an absorption maximum halfway between the peaks of rhodopsins and of porphyropsins and belonging to the retinene(1) system characteristic of rhodopsins. The pigment is therefore named a retinene(1) pigment 512 of the mudsucker, Gillichthys mirabilis. It is uncertain whether this type of photosensitive pigment will be found in other euryhaline fishes.

Animals↗
PubMed2004

The safety and efficacy of the 308-nm excimer laser for pigment correction of hypopigmented scars and striae alba.

OBJECTIVE: To assess the safety and efficacy of the 308-nm excimer laser in pigment correction of hypopigmented scars and striae alba. DESIGN: Institutional review board-approved randomized controlled trial. SETTING: Private research center. PATIENTS: Volunteer sample of 31 adult subjects with hypopigmented scars or striae alba distributed on the face, torso, or extremities. INTERVENTIONS: Lesions were randomized to receive treatment or not, with site-matched normal control areas. Treatments were initiated with a minimal erythema dose minus 50 mJ/cm(2) to affected areas. Subsequent treatments were performed biweekly until 50% to 75% pigment correction, then every 2 weeks thereafter until a maximum of 10 treatments, 75% increase in colorimetric measurements, or 100% visual pigment correction. MAIN OUTCOME MEASURES: Pigment correction by visual and colorimetric assessments compared with untreated control lesions and site-matched normal skin before each treatment and at 1-, 2-, 4-, and 6-month follow-up intervals. Occurrence of erythema, blistering, dyspigmentation, or other adverse effects was monitored. RESULTS: The percentage pigment correction by both assessments increased in direct proportion to the number of treatments. The mean percentage pigment correction by visual assessment relative to control of 61% (95% confidence interval [CI], 55%-67%) for scars and 68% (95% CI, 62%-74%) for striae was achieved after 9 treatments. The mean percentage pigmentation by colorimetric measurements relative to control of 101% (95% CI, 99%-103%) for scars and 102% (95% CI, 99%-104%) for striae was achieved after 9 treatments. Both sets of values gradually declined toward baseline levels during the 6-month follow-up. No blistering or dyspigmentation occurred. CONCLUSIONS: Therapy with the 308-nm excimer laser is safe and effective in pigment correction of hypopigmented scars and striae alba. Mean final pigment correction rates relative to control sites of approximately 60% to 70% by visual assessment and 100% by colorimetric analysis were observed after 9 treatments administered biweekly. Maintenance treatment every 1 to 4 months is required to sustain the cosmetic benefit.

Abdomen↗
PubMedDate not supplied

Mucin glycoprotein content of human pigment gallstones.

Mucin glycoproteins, a secretory product of the gallbladder, are thought to contribute to the matrix or nucleus of gallstones. Human black pigment stones originate in the gallbladder and have as their major constituent calcium bilirubinate, as well as inorganic salts and small amounts of cholesterol. The object of this study was to estimate the amount of glycoprotein in black pigment stones and to isolate gallbladder mucin from dissolved stones. Black pigment stones containing 18 to 65% calcium bilirubinate were first dissolved in 12.5 mM EDTA/0.1 N NaOH and decolorized, then subjected to glycoprotein assay. The mean glycoprotein content of eight stones was 12.4%. In separate experiments, pigment stones were partially dissolved by brief exposure to EDTA/NaOH to minimize glycoprotein breakdown, and the glycoproteins isolated by gel filtration and ultracentrifugation. Pigment stones contained two glycoprotein fractions on Sepharose 4B; a high molecular weight mucin glycoprotein in the void volume and a lower molecular fraction in the included volume. Mucin was further purified by density gradient ultracentrifugation in cesium chloride. Three separate mucin fractions had an average buoyant density of 1.48 gm per ml which is typical for these glycoproteins. Bile pigment was associated with high molecular weight mucin even after extensive dialysis, gel filtration, and density gradient ultracentrifugation. The identity of mucin was further established by beta-elimination of glycoproteins in alkaline borohydride which yielded galactosaminitol from cleavage of O-glycosidic bonds. Our results indicate that mucin glycoproteins are present in significant concentrations in human black pigment stones and can be purified from stones solubilized in EDTA/NaOH. The association of bile pigment with gallbladder mucin, even after extensive purification, is consistent with the hypothesis that mucin contributes to the matrix of pigment gallstones.

Bilirubin↗
PubMed1978

Ultrastructure of the extracutaneous pigment cells in the plaice (Pleuronectes platessa, L., Teleostei).

The extracutaneous pigment cell system of the plaice (Pleuronectes platessa L.) was examined by light and electron microscopy in selected regions, including two cutaneous regions for comparison. The extracutaneous pigmentation consists of guanocytes and melanocytes with differing distributions within the body. The eyeless side lacks melanocytes. The pigment cells are differentiated as very flat elements with long processes. They display an affinity for loose connective tissue at boundary layers such as the peritoneal epithelium, organ capsules or blood vessels, to which they are parallelly arranged at a very constant distance. In some locations guanocytes are intimately associated with melanocytes forming "reduced chromatophore units". Extracutaneous pigment cells are poor in mitochondria, endoplasmic reticulum, microfilaments, caveolae intracellulares, ribosomes and glycogen granules, all of which are more abundant in cutaneous pigment cells and pigment cells of the eye. In extracutaneous guanocytes the crystals are loosely arranged parallel to the cell surface, in cutaneous guanocytes perpendicular. Cells with rod-like vesicular cisternae are described as "guanoblasts". No single pigment cell was found exhibiting different types of pigment granules. The varying colors of extracutaneous pigmentation arise from varying combinations of guanocytes and melanocytes in addition to the color of the tissue itself.

Animals↗
PubMed2002

Genetic analysis of floral anthocyanin pigmentation traits in Asiatic hybrid lily using molecular linkage maps.

To understand the genetic background of two floral anthocyanin pigmentation traits, anthocyanin pigmentation in the flower tepals and spot formation, in the Asiatic hybrid lily (2n = 24), segregation of the two traits among 96 F(1) plants derived from a cross between commercial cultivars 'Montreux' and 'Connecticut King' were investigated. 'Montreux' has anthocyanin pigmentation in the tepals with many spots, and 'Connecticut King' has flowers with carotenoid pigmentation without spots. The F(1) plants with or without anthocyanin pigment in the tepals segregated with a 1:1 segregation ratio, indicating that a single gene controls anthocyanin pigmentation in the tepals. The number of spots per square centimeter of all tepals showed continuous distribution in the F(1) plants. To map the loci for the two anthocyanin pigmentation traits, molecular linkage maps in the Asiatic hybrid lily were constructed using a double pseudo-testcross strategy, with the same F(1) plants used for phenotypic evaluation, and 212 PCR-based DNA markers. The trait for anthocyanin pigmentation in tepals was used as a trait marker. The map of 'Montreux' comprised 95 markers in 26 linkage groups, and the map of 'Connecticut King' used 119 markers in 24 linkage groups. The total map lengths were 867.5 and 1,114.8 cM, respectively. The trait locus for anthocyanin pigmentation in the tepals was between markers ASR35-180 and P506-40 in linkage group 1 of the 'Montreux' map with a map distance of 1.2 cM and 2.6 cM, respectively. A single-point analysis of quantitative trait loci (QTLs) for tepal spot number identified two putative QTLs in linkage groups 1 and 19 of the 'Connecticut King' map. One putative QTL in linkage group 19 explained 64% of the total phenotypic variation. Because both putative QTLs were mapped on the linkage map of 'Connecticut King' that has no spots, dominant alleles of them might suppress spot formation.

Journal Article↗
PubMed2005

Imipramine-induced facial pigmentation: case report and literature review.

BACKGROUND: Patients who present with facial pigmentation can be a diagnostic challenge. OBJECTIVE: The goal of this study was to discuss the diagnosis and management of imipramine-induced facial pigmentation. METHODS: We describe a patient with facial pigmentation of 26 years' duration that was associated with imipramine treatment for depression. We discuss light and election microscopic findings and review 11 previously reported cases of imipramine-induced skin pigmentation. RESULTS: Examination showed blue-gray facial pigmentation. Light microscopy showed perivascular pigment granule deposits in the upper dermis that stained positively with Fontana-Masson stain and negatively with Prussian blue stain. Electron microscopy showed electron-dense bodies within histiocytes without clearly identifiable melanin granules, consistent with drug-induced pigmentation. Six weeks after switching to sertraline the patient reported a slight improvement of her cutaneous pigmentation. CONCLUSION: Imipramine is a rare cause of gray-blue facial pigmentation. Light microscopy consistently shows granular dermal deposits that stain positively with Fontana-Masson stain but negatively with iron stain.

Adrenergic Uptake Inhibitors↗
PubMed1998

Ultrastructural and functional study of the liver pigment cells from Rana esculenta L.

A study of the liver pigment cells of Rana esculenta L. has been performed on both liver in toto and cells in culture. Ultrastructural and cytochemical analyses showed a close relationship between this visceral pigment cell system and the cells of hepatic macrophage lineage. Like the latter, the liver pigment cells present phagocytic activity, in the sinusoids and in vitro, and give a positive response to tests for peroxidase and lipase. The liver pigment cells are isolated, together with the Kupffer cells, from the sinusoidal cell fraction of the liver. In culture, they maintain their melanogenetic ability, demonstrated by the presence of dopaoxidase activity in the soluble, membranous, and melanosome fractions. Analysis of the cultures showed that as culture time increased, so did melanosome dopaoxidase activity, the number of pigmented fields, and the level of pigmentation of the cells. The values of dopaoxidase activity of the pigment cells in culture show the same seasonal oscillations as the system in toto, indicating that the cells maintain an internal clock, at least in the first 72 h of culture. There is evidence that the pigment cells are macrophages which can express a melanogenetic function. Our results and other experimental data provide a basis for hypothesizing that the pigment cells in Rana esculenta L. liver may derive from, or have a common origin with, the Kupffer cells.

Animals↗
PubMed1994

Biotechnological applications of research on animal pigmentation.

The implications of primary research on pigmentation for the colour manipulation of animal species of economic importance, and the facilitation of specific processes in biotechnology are discussed. Pigment technologists, especially poultry and fish nutritionists, are concerned with achieving the often specific type and degree of coloration demanded by consumers of various products (notably egg yolk, eggshell, broiler skin and salmon flesh). In most instances involving melanin (pelage, plumage and integument) and porphyrin (eggshell) pigments, the desired coloration is achieved through the use of alternate alleles at gene loci controlling the characters of interest. In contrast, coloration involving carotenoids is controlled primarily through pigment supplementation in the diet. The difference between carotenoids and other pigments involves the strict dietary origin of the former. Factors other than pigment availability, such as body condition, hormonal status and genetic constitution, also affect coloration. Although day-old chicks can be sexed by visual inspection of their genitalia, matings resulting in sex-associated phenotypes are in wide use. The genetic markers involved affect the colour of the plumage. The cloning of genes involved in pigmentation offers the prospect of deciphering the genetic control of animal pigmentation and modifying it to meet specific pigmentation needs.

Journal Article↗
PubMed2004

Effects of chemical functional groups on the polymer adsorption behavior onto titania pigment particles.

The effects of functional groups on polymer adsorption onto titania pigment particles have been investigated as a function of pH and ionic strength using polyacrylic acid and modified polyacrylamides. The polyacrylamides include the homopolymer, an anionic copolymer with hydroxyl and carboxylate group substitution, and a nonionic copolymer with hydroxyl group substitution. Adsorption isotherms and infrared spectroscopy were used to examine the polymer-pigment interactions. The adsorption of the polyacrylic acid and anionic polyacrylamide on titania pigment is greatest when electrostatic repulsion is absent or reduced. At low pH values, below the pigment isoelectric point (IEP), or at high ionic strength, the adsorption density of the anionic polymers on titania pigment is high, while at higher pH values above the pigment IEP, the adsorption density decreases. But the adsorption of nonionic polymers on titania pigment is not influenced by either ionic strength or pH. Acrylamide groups were found to hydrogen bond with the titania pigment surface, independent of pH. With the inclusion of hydroxyl functional groups into the polyacrylamide chain, the polymer adsorption density increased without increased adsorption affinity. Carboxylate functional groups in the anionic polymers strongly interact with the pigment surface, producing the highest adsorption density at low pH values. All polymers exhibit Langmuir adsorption behavior with hydrogen bonding found as the dominant mechanism of adsorption in addition to electrostatic interaction occurring for the anionic polymers.

Journal Article↗
PubMed1998

Quantification of aqueous melanin granules in primary pigment dispersion syndrome.

PURPOSE: Aqueous melanin granules are essential in the pathogenesis of pigment dispersion syndrome and pigmentary glaucoma. We quantified aqueous melanin granules with the laser flare-cell meter in patients with pigment dispersion syndrome, assessed the measurement reproducibility, and correlated the numbers with clinical findings. METHODS: Aqueous melanin granules were counted by means of the cell count mode of the laser flare-cell meter (KOWA FC-1000; Kowa, Tokyo, Japan) in 42 eyes of 21 patients with primary pigment dispersion syndrome under three conditions (undilated pupils, dilated pupils, after exercise). The reproducibility of the measurements was determined with the intraclass correlation coefficient. A control group of 40 age- and sex-matched eyes was also examined after pupillary dilation. The results were correlated with biomicroscopic findings in eyes with pigment dispersion syndrome (retrocorneal Krukenberg spindle, iris transillumination, pigmentation of trabecular meshwork). RESULTS: Numerous aqueous melanin granules were detected in eyes with pigment dispersion syndrome (mean, 2.9 +/- 3.7 granules/0.075 mm3) but only small numbers were counted in normal eyes (0.2 +/- 0.3, P < .001). Medical pupil dilation caused an additional increase of aqueous melanin granules in pigment dispersion syndrome (6.3 +/- 5.3, P < .001), but not undilated exercise (climbing stairs) (2.9 +/- 3.7, P > .5). The reproducibility of the measurements was very high (intraclass coefficient >0.92). The number of melanin granules correlated with the degree of Krukenberg spindle (r = .61, P = .004) and with iris transillumination (r = .69, P = .001). CONCLUSIONS: Quantification of aqueous melanin granules yields reproducible results and shows increased numbers in pigment dispersion syndrome, especially after pupillary dilation. Aqueous melanin granule quantification may be useful for evaluating eyes with pigment dispersion syndrome and for assessing treatment effects.

Adult↗
PubMed2006

Establishment of an extraction method for the recovery of tattoo pigments from human skin using HPLC diode array detector technology.

Tattooing is a widespread process of puncturing pigments into skin, whereas the resulting concentration inside the skin remains unknown. Many tattoo colorants are organic pigments, such as azo pigments, manufactured for other uses. To remove tattoos from skin, laser pulses at very high intensities are applied to the skin to destroy the tattoo pigments. Recent investigations have shown that several azo compounds are cleaved by laser light leading to potentially toxic or carcinogenic compounds. To assess the risk of tattooing and laser treatment of tattoos, the concentration of the pigments and their decomposition products in the skin must be determined. Therefore, an extraction method was established to determine the concentration of tattoo pigments and decomposition products quantitatively. The extraction of two widely used azo compounds, Pigment Red 22 and Pigment Red 9, and their laser-induced decomposition products, 2-methyl-5-nitroaniline, 4-nitrotoluene, 2,5-dichloraniline, and 1,4-dichlorobenzene, was accomplished using recovery experiments and HPLC-DAD technology. Despite the poor solubility of the pigments, a nearly complete recovery from aqueous suspension (> 92%) or lysed skin (> 94%) was achieved. The decomposition products were extracted from aqueous suspension or skin showing a recovery of up to 100%, except for the very volatile 1,4-DCB.

Azo Compounds↗
PubMed2000

Inorganic yellow-red pigments without toxic metals

Inorganic pigments have been utilized by mankind since ancient times, and are still widely used to colour materials exposed to elevated temperatures during processing or application. Indeed, in the case of glasses, glazes and ceramics, there is no alternative to inorganic pigments for colouring. However, most inorganic pigments contain heavy metals or transition metals that can adversely effect the environment and human health if critical levels are exceeded. Cadmium-based pigments in particular are a cause of concern: although the pigments are not toxic due to their very low solubility in water and dilute mineral acids, cadmium itself is toxic and can enter the environment in a bioavailable form through waste-disposal sites and incineration plants. This has led to regulations, based on the precautionary principle, that strongly restrict the use of cadmium pigments. And even though recent assessments have concluded that the risk to humans or the environment might be not as significant as originally feared, a strong demand for inherently safer substitutes remains. Here we demonstrate that solid solutions of the perovskites CaTaO2N and LaTaON2 constitute promising candidates for such substitutes: their brilliance, tinting strength, opacity, dispersability, light-fastness and heat stability rival that of the cadmium pigments, while their colour can be tuned through the desired range, from yellow through orange to deep red, by simple composition adjustments. Because all the constituent elements are harmless, this perovskite-based inorganic pigment system seems a promising replacement that could eliminate one of the sources for cadmium emissions to the environment and some of the remaining concerns about pigment safety.

Journal Article↗
PubMed2001

Iridial pigmentation induced by latanoprost ophthalmic solution in Japanese glaucoma patients.

PURPOSE: To investigate the incidence of iridial pigmentation induced by latanoprost ophthalmic solution in Japanese glaucoma patients by a prospective and observer-masked study. PATIENTS AND METHODS: Sixty-nine eyes of 69 glaucoma patients were included. Patients who had undergone intraocular surgery, laser trabeculoplasty, and laser iridotomy within 12 months before enrollment, and patients with history of uveitis and any changes in antiglaucoma drugs within 6 months before enrollment were excluded. Iridial photographs were taken by one examiner under the same conditions at 1, 3, and 6 months after the initiation of latanoprost treatment. Three glaucoma specialists, masked of patient information, independently assessed the iridial pigmentation. Cases with iridial pigmentation diagnosed by three specialists were categorized as showing a definite increase in iridial pigmentation. RESULTS: A definite increase in iridial pigmentation occurred in 3.5%, 9.7%, and 35.0% of eyes within 1, 3, and 6 months of treatment, respectively. Age, gender, or concomitantly used eyedrops did not significantly influence the incidence of iridial pigmentation within 6 months of instillation. A reduction of intraocular pressure by latanoprost did not differ significantly between patients with and without iridial pigmentation. CONCLUSION: The incidence of iridial pigmentation by latanoprost ophthalmic solution in Japanese patients was higher than previously reported values in pigmented races.

Adult↗
PubMed2005

Flipped scleral flap surgery for reduction of ocular pigmentation in oculodermal melanosis.

PURPOSE: To report on surgical reduction of oculodermal melanosis in 6 patients presenting with severe episcleral pigmentation. METHODS: After informed consent was obtained, surgical reduction of ocular pigmentation with ocular dermal melanosis was performed on 3 children, 2 girls and 1 boy male, who were cosmetically handicapped. After conjunctival peritomy, rectangular scleral free flaps were created using lamellar dissection, usually in the nasal or temporal quadrants. The rectangles extended from just posterior to the rectus muscle insertion. These free flaps were flipped over and reattached to the scleral bed, hiding the episcleral pigmentation internally and resulting in a less pigmented surface being visible. The superficial scleral nevus and the nevus adjacent to the limbus were peeled using a blade. RESULTS: In all cases, episcleral pigmentation was reduced with satisfactory cosmetic improvement, but mild scleral pigmentation and conjunctival scarring remained. During the 37-month mean follow-up period, no complications were observed. CONCLUSIONS: Patients with oculodermal melanosis often complain of globe pigmentation as well as face pigmentation. Serial follow-up was needed because some reports indicate development of choroidal melanoma occurs in oculodermal melanosis. To the best of our knowledge, this is the first report of successful surgical reduction of ocular pigmentation in oculodermal melanosis.

Adolescent↗
PubMed1993

Pigments induce folding of light-harvesting chlorophyll a/b-binding protein.

The conformational behaviour of the light-harvesting chlorophyll a/b-binding protein (LHCP), the apoprotein of the major light-harvesting complex (LHCII) of photosystem II in plants, has been studied. According to the circular dichroism in the ultraviolet range measured with isolated LHCII, the protein in the complex adopts a folded structure with a high content of alpha helix (about 60%), whereas the non-pigmented, solubilized protein has a less ordered structure (about 20% alpha helix). LHCP-pigment complexes that have been reconstituted from the overexpressed protein and isolated pigments in the presence of detergents display a protein CD signal similar to that of authentic LHCII, indicating that LHCP folds into the native structure during the reconstitution procedure. Renaturation of LHCP in these experiments is dependent on the presence of pigments and the formation of stable LHCP-pigment complexes. Pigment-induced engagement of LHCP in a compact structure has also been shown by two additional experimental approaches. (a) Upon complex formation, LHCP or its precursor (pLHCP) becomes resistant to trypsin digestion with the exception of an N-terminal segment of the protein; the same protection of LHCP is known to occur in intact thylakoids. (b) Pigment binding renders a cysteine residue within the N-proximal hydrophobic domain of the protein as well as a newly introduced cysteine four amino acid positions from the C terminus inaccessible to modification with a sulfhydryl-specific label whereas the N terminus stays susceptible to specific labelling. These observations support the notion that only the N terminus protrudes from a compact protein-pigment structure in LHCII. The fact that the major part of LHCP is trypsin-resistant in pigmented complexes reconstituted in the absence of a membrane or even lipids justifies caution in using protection against trypsin as a criterion for the integration of LHCP into the thylakoid membrane.

Apoproteins↗