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PubMed1978

Pigment gallstone composition in cirrhotic and noncirrhotic subjects.

The composition of pigment gallstones from patients with and without cirrhosis was compared. Carbonate-containing pigment stones were distinguished from noncarbonate stones by infrared spectroscopy. Calcium was the major cation of each stone group. The major anion in noncarbonate pigment stones was bilirubinate or phosphate, but was carbonate in carbonate stones. The composition of pigment stones from cirrhotic and noncirrhotic patients was similar except that significantly less carbonate was present in carbonate stones, and less pigment (bilirubinate) was present in noncarbonate stones from noncirrhotics. These data suggest that irrespective of the presence of cirrhosis, the formation of noncarbonate pigment stones involves the selective precipitation of calcium bilirubinate and phosphate, whereas carbonate stone formation involves the selective precipitation of calcium carbonate.

Age Factors↗
PubMed1992

A role for microglia in the maintenance of photoreceptors in retinal transplants lacking pigment epithelium.

Studies on intact retina have pointed to a necessary role for retinal pigment epithelium in the maintenance of photoreceptor outer segments and for regeneration of visual pigment. However, it has been shown that when embryonic retinae are separated from the pigment epithelium and transplanted into the brain of neonatal rats, the transplanted photoreceptors develop outer segments and the retina responds to light in the apparent absence of pigment epithelial cells. We confirm that there are no retinal pigment epithelium cells associated with transplanted retinae in the present series of experiments and show that a row of cells, composed predominantly of microglia of host origin, border the graft. These cells can be seen to contain engulfed outer segments when they are apposed to the outer retina, suggesting that the microglia have assumed, at the least, the phagocytic function normally associated with retinal pigment epithelium. Microglial cells and their processes are also found within the transplant, but these cells are typically devoid of phagosomes, indicating an absence of phagocytic activity. The close physical association of these resting microglia with the transplant may facilitate their role in antigen presentation under specific conditions of immune provocation.

Animals↗
PubMed1993

High vesicular cholesterol and protein in bile are associated with formation of cholesterol but not pigment gallstones.

To examine the differentiating parameters between cholesterol and pigment gallstones, we compared the nucleation times, concentrations of biliary lipid and protein, and the distribution of vesicular cholesterol in gallbladder bile of 16 patients with cholesterol, eight patients with black pigment gallstones, and nine gallstone-free control patients. Cholesterol monohydrate crystals were present in the fresh bile of only the cholesterol gallstone group. The nucleation time was significantly faster in the cholesterol stone group (3.3 +/- 3.2 days) than in the other two groups (pigment stone: 15.8 +/- 6.6, control: 16.9 +/- 5.7). The cholesterol saturation indices and the distribution of vesicular cholesterol were significantly higher in the cholesterol gallstone group than those in the other two groups. The total biliary protein concentration was significantly (P < 0.01) higher in the cholesterol gallstone group [2.57 +/- 1.91 (SD) mg/ml] than that in the black pigment stone group (1.09 +/- 0.59). All parameters in patients with black pigment gallstone were essentially similar to the controls. We conclude that the presence of cholesterol crystals, rapid nucleation time, high vesicular cholesterol distribution, elevated cholesterol saturation index, and high protein concentration are associated with cholesterol gallstones but not with black pigment gallstones.

Aged↗
PubMed1990

Bile acid composition in brown pigment stones.

The bile acids in brown pigment stones and gallbladder bile were fractionated into free acids, glycine and taurine conjugates, and sulfates using diethylaminohydroxypropyl Sephadex LH-20 (DEAP-LH-20) column chromatography and were quantitated by gas chromatography. Twenty-eight cases of brown pigment stones were studied and divided into two groups: those with and those without bacteria possessing bile acid-deconjugating activity. In the former, free bile acid amounted to 62 +/- 34% of the total bile acid, while in the latter, only 0.1% of total bile acid was free bile acid. The fraction of total bile acid made up of free bile acids was found to be consistently higher in brown pigment stones than in the corresponding bile, irrespective of the presence or absence of biliary infection. Free bile acid is present in negligible amounts in normal bile. Total bile acid concentration in the bile of patients with brown pigment stones was significantly less than that of controls (13 vs 50 mg/ml). Biliary infection is almost always present in cases with brown pigment stones. These findings suggest that bacterial infection is present at the initiation of brown pigment stone formation as well as during the period of ensuing stone growth.

Bacterial Infections↗
PubMed2003

Altered impedance during pigment aggregation in Xenopus laevis melanophores.

Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.

Animals↗
PubMed1988

Pigmentation changes in brevibacteria induced by mutagenic treatment.

Inducible pigmentation changes were observed in pigmented strains of Brevibacterium sp. M27 and B. flavum treated with N-methyl-N'-nitro-N-nitrosoguanidine. The highest frequency of induction was reached already at a survival of 30-40% with the maximal yield of 6-10%. As compared with the initial yellow colour, three new pigmentation types, viz. white, pink and orange, were observed. The yellow pigmented parent strains are most resistant to the lethal effects of UV radiation. By selecting pigmented mutants of all types on media containing antibiotics it was possible to obtain strains that were resistant either to tetracycline or to streptomycin. Auxotrophic pigmented mutants were also isolated. In multiple mutant strains of Brevibacterium sp. M27 a number of strainsexhibited a changed L-lysine production. In some strains the production was variable, whereasother strains did not produce L-lysine at all and stains with a limited production of other amino acids were also detected.

Brevibacterium↗
PubMed2004

Off-line separation and determination of rare earth elements associated with chloroplast pigments of hyperaccumulator Dicranopteris dichotoma by normal-phase liquid chromatography and ICP-MS.

An off-line normal-phase liquid chromatography-ICP-MS method has been used for separation and determination of the rare earth elements (REE) associated with chloroplast pigments of Dicranopteris dichotoma. The stability of REE-bound pigments was tested, and almost no destruction of REE-bound pigments occurred during the so-called normal-phase liquid chromatography. The accumulated free REE ions on the microcrystalline cellulose column were cleaned by elution with 5 mmol L(-1) 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507), to avoid exchange of these free ions with metals from the pigments. When these precautions were taken, the method was applied to the study of REE-bound pigments in D. dichotoma. ICP-MS results showed REE were present in chlorophylls and lutein, although REE concentrations in carotene and pheophytin were both below procedural blank levels. By careful analysis of the eluate fractions containing chlorophyll a it was found that REE-bound chlorophyll a in D. dichotoma was slightly enriched in the fractions with relatively short retention time. Results indicated that the retention time of REE-bound chlorophyll a might be slightly less than that of magnesium chlorophyll a, and REE-bound chlorophylls might be of relatively low polarity in comparison with magnesium bound chlorophylls. This phenomenon could be explained by the special double-decker sandwich-structure of REE-bound chlorophylls, as was reported by us and other authors. On the basis of these results we preferred to consider that REE can replace magnesium in chlorophyll a of D. dichotoma, and that the role of REE-bound chlorophylls in photosynthesis cannot be neglected. These data might be useful for understanding of both the properties of REE-bound pigments and the effect of REE on plant photosynthesis.

Chlorophyll↗
PubMed2002

[Follow-up of proliferation of juxtapapillary retinal pigment epithelium].

PURPOSE: Bengin proliferation of the juxtapapillary retinal pigment epithelium is a rare but important tumor because it may be mistaken for a malignant lesion such as choroidal melanoma. CASE REPORT: A 9-year-old male patient consulted our clinic first in 1991 because of a reduction in visual acuity due to a tumor of the optic nerve head in the left eye. Visual acuity was 1.0 in the right eye and 0.2 in the left eye. Slit lamp examination and intraocular pressure were regular in both eyes. Kinetic perimetry showed a enlarged blind spot besides regular isopters. Funduscopy revealed a pigmented, ill-defined prominence of the optic nerve head with a mossy surface. In annual examinations were found a slowly progredient reduction in visual acuity up to 0.04 durning the last visit in January 2000 as well as a enlargement of the blind spot due to an increasing prominence and pigmentation of the optic nerve head. Because of the clincal aspect, the slowly progressive course, the enlargement of the blind spot with deterioration of vision and especially the florescein angiography, which revealed peripapillary capillary alterations with leakage, we diagnosed a proliferation of the juxtapapillary retinal pigment epithelium. CONCLUSION: The proliferation of the juxtapapillary retinal pigment epithelium can be differentiated from other pigmented tumors of the optic nerve head by its typical clinical aspect and course and especially by using flourescein angiography.

Capillary Leak Syndrome↗
PubMed2005

Visual pigment absorbance and spectral sensitivity of the Mysis relicta species group (Crustacea, Mysida) in different light environments.

Visual-pigment absorbance spectra and eye spectral sensitivities were examined in eight populations of opossum shrimp from different light environments. Four Finnish populations, two from the Baltic Sea and two from freshwater lakes, represent Mysis relicta, sensu stricto. The sibling species M. salemaai and M. diluviana are represented by, respectively, two Baltic Sea populations and two populations from freshwater lakes in Idaho, USA. In M. relicta, the visual pigments of the two lake populations were similar (lambda(max)=554.3+/-0.8 nm and 556.4+/-0.4 nm), but significantly red-shifted compared with the sea populations (at 529 and 535 nm) and with M. salemaai (at 521 and 525 nm). All these pigments had only A2 chromophore and the lake/sea difference indicates adaptive evolution of the opsin. In M. diluviana, lambda(max) varied in the range 505-529 nm and the shapes of spectra suggested varying A1/A2 chromophore proportions, with pure A1 in the 505 nm animals. Eye sensitivity spectra were flatter and peaked at longer wavelengths than the relevant visual-pigment templates, but declined with the same slope beyond ca. 700 nm. The deviations from visual-pigment spectra can be explained by ocular light filters based on three types of identified screening pigments.

Animals↗
PubMed2005

Zinc uptake and storage: the role of fundus pigmentation.

BACKGROUND: Age-related macular degeneration (AMD) is associated with lower melanin pigmentation and is more prevalent among the elderly Caucasian population than among Africans. A correlation between light iris colour, fundus pigmentation and the incidence of AMD is reported. Moreover, melanin represents the main storage of zinc in the eye. Zinc enhances antioxidant capacity through its function as a cofactor of important enzymes or by influencing gene expression of regulatory elements in the eye. In this study, we investigated the uptake and storage of zinc in the human choroid/retinal pigment epithelium (RPE) complexes in dependence on the fundus pigmentation as judged by the iris colour. MATERIAL AND METHODS: Choroid/RPE complexes of blue and brown human eyes were used. Tissues without any substitution served as controls. Specimens from choroid/RPE complexes were incubated with 100 microM zinc chloride for 24 h. After incubation, pieces of the complexes were stored to investigate the uptake of zinc. The rest of the tissues were kept for 3 and 7 days in culture medium (DMEM) for storage examination. The concentration of zinc was measured by inductively coupled plasma mass spectrometry. RESULTS: After 24 h of zinc treatment the concentration of zinc in the choroid/RPE complexes of blue eyes was not significantly increased. The concentration of zinc in highly pigmented tissues (brown eyes) was increased by the factor 5.1 after 24 h and remained at high levels after 3 days (factor 4.4) and 7 days (factor 2.8). CONCLUSIONS: Zinc uptake in the choroid/RPE complex correlates to the iris colour. Alterations of the degree of iris pigmentation result in differences of zinc uptake and storage in the choroids. A potential protective role of zinc may be more prominent in dark- than in light-coloured eyes.

Adult↗
PubMed2000

Retinal pigment epithelial autotransplantation: morphological changes in retina and choroid.

BACKGROUND: Replacement of degenerating retinal pigment epithelial (RPE) cells has been proposed to promote photoreceptor survival in retinal pigment epithelial disease. However, allografts of RPE have a higher rate of immunological rejection. The investigators studied the effects of autotransplantation of RPE on the morphological changes in photoreceptors and choriocapillaris. METHODS: RPE autotransplantation (wound type 1) was performed in 25 rabbits and compared with wounds following debridement of the RPE (wound type 2). Light and electron microscopy and scanning electron microscopy of choroidal vascular casts were performed at 3, 7, 14 and 30 days after surgery. Quantitative analysis of the choriocapillaris bed area was performed by automated image analysis and the results were analyzed by paired Student's t-test. RESULTS: Retinal pigment epithelium was found to be monolayered and ill-differentiated at day 7. Differentiation occurred at day 30, with preservation of photoreceptors and other layers of the neurosensory retina in type 1 wounds. Type 2 wounds showed atrophy of the regenerating retinal pigment epithelium at day 14 and day 30 with loss of overlying photoreceptor cell layer. There was significant choriocapillaris regeneration in type 1 wounds compared to the type 2 wounds at day 7 (P=0.045), day 14 (P=0.028) & day 30 (P=0.06). CONCLUSIONS: Retinal pigment epithelial autotransplantation significantly reduced photoreceptor degeneration and choriocapillaris atrophy associated with loss of retinal pigment epithelium. This procedure supports the hypothesis that RPE autotransplantation may be helpful in geographic atrophy and conditions requiring submacular surgery.

Animals↗
PubMed2006

New violet 3,3'-bipyridyl pigment purified from deep-sea microorganism Shewanella violacea DSS12.

We have purified a new violet pigment derived from Shewanella violacea DSS12 to determine its chemical structure. The pigment colored blue in tetrahydrofuran (THF) or chloroform and showed a broad absorption spectrum from 500 to 700 nm. X-ray diffraction analysis of single crystals showed that the chemical structure of this pigment was 5,5'-didodecylamino-4,4'-dihydroxy-3,3'-diazodiphenoquinone-(2,2'), containing the same chromophore as an indigoidine known as microbial blue pigment. The violet color of this pigment was due to hypsochromic shift (blue shift) caused by the side-by-side orientation of this pigment molecule, revealed by X-ray structural analyses of a single crystal.

Chloroform↗
PubMed2006

An animal model of black pigment gallstones caused by nanobacteria.

Black pigment gallstones are often founded in gallbladder, but their pathogenesis is unclear. The present study was undertaken to study the role of nanobacteria in pigment gallstone formation in Japanese white rabbits. Nanobacteria were successfully cultured from 3 of 7 cholecystolithiasis patients gallbladder (without acute cholecystitis) bile samples and affirmed by Hoechst 33258 staining and specific immunostaining using monoclonal antibody. Nanobacteria were injected into rabbits' gallbladder. After 2 weeks follow-up, the incidence of black pigment gallstones in rabbits was significantly greater in nanobacteria-injected group (8/10) than that in DMEM-injected group (2/10) and that in hydroxyapatite-injected group (2/10). This study indicates that nanobacteria exists in gallbladder bile of cholelithiasis patients and causes the formation of black pigment gallstones in rabbits. For the first time, we successfully established an animal model of black pigment gallstones caused by nanobacteria. This will be helpful in further delineating the pathogenesis of black pigment gallstones.

Animals↗
PubMed1977

The pigment dispersion syndrome.

The pigment dispersion syndrome was noted in 10% of white and black subjects with and without glaucoma. This suggested pigment dispersion was not a high risk factor in the development of glaucoma. The HLA-B7 antigen was less prevalent and HLA-B13 and Bw17 antigens were significantly more prevalent in individuals with the pigment dispersion syndrome than in subjects without the syndrome. Either HLA-B13 or Bw17 antigen was found in 23 (77%) of 30 patients with the pigment dispersion syndrome and in only 13 (6%) of the 203 subjects without pigment dispersion. Pigmentary glaucoma was characterized by a significantly higher prevalence of combinations of HLA-B12 and B13 or HLA-B12 and Bw17 antigens as compared to the pigment dispersion syndrome without glaucoma, primary open-angle glaucoma, or the general population. This suggested that pigmentary glaucoma differed genetically from primary open-angle glaucoma and was a separate entity.

Glaucoma↗
PubMed1985

Relationship of senile macular degeneration to ocular pigmentation.

We prospectively evaluated 650 consecutive white patients with senile macular degeneration and compared them to a control group of 363 patients. Ocular pigmentation (iris color and fundus pigmentation) was recorded for each patient, as was hair color (as a child and young adult) and age at evaluation. Patients were from the New England states and Florida. Our most significant finding was that 494 patients with senile macular degeneration (76%) had light-colored irides compared with 145 of the controls (40%). Fundus pigmentation closely corresponded to iris pigmentation (P less than 0.01). Hair color was blond or light brown in 370 of the patients with senile macular degeneration (57%) and in 105 of the controls (29%). Further, there was a tendency for individuals with lightly pigmented irides to have senile macular degeneration at an earlier age than those with dark irides (P less than .01). Thus, increased ocular pigmentation tends to decrease the risk of developing senile macular degeneration.

Aged↗
PubMed1977

Pigment binding of copper in human bile.

The copper profile of human bile was studied using a Cu-free preparative polyacrylamide gel system. 85 percent and 91 percent of the Cu in the bile of two subjects was found in a leading pigmented band with no additional detectable copper in the remainder of the gel in either subject. The content of the pigmented band was recovered from the gel by an intermediate electrophoretic technique. Subsequent n-butanol extraction removed contaminating bile salts with the formation of a Cu containing pigmented precipitate. Using thin-layer cellulose chromatography this precipitate was separated into two pigments which on the basis of color and diazotization reaction were believed to be conjugated bilirubins. Addition of Cu transformed the pigments into biochemically different species. 64Cu verified copper binding by the altered pigments.

Bile↗
PubMed1985

A marker of animal-vegetal polarity in the egg of the sea urchin Paracentrotus lividus. The pigment band.

We have examined the subequatorial accumulation of pigment granules (the so-called 'pigment band') in the egg of the sea urchin Paracentrotus lividus, which constitutes an unambiguous marker of animal-vegetal polarity. Most of the reddish pigment granules are situated at the periphery of the egg. They exhibit occasional saltatory movements and can aggregate into large patches. Pigment granules are retained as a band in the isolated cortex when the egg surface complex is isolated by shearing eggs attached to polylysine-coated surfaces with calcium-free isotonic solutions. Pigment granules remain as the main vesicular component of fertilized egg cortices or of unfertilized egg cortices perfused with calcium to provoke cortical granule exocytosis. They may be anchored to the isolated cortex through associations with the plasma membrane and with an extensive subsurface network of rough endoplasmic reticulum (rough ER). Pigment granules contain antimonate-precipitable calcium and, in this respect and many others, resemble acidic vesicles recently identified in the cortex of unpigmented sea urchin eggs. We discuss the similarities observed between granules and acidic vesicles in various urchin egg species and their possible functions.

Actin Cytoskeleton↗
PubMed1985

Simplified concanavalin-A sepharose adsorption method for separation of cone visual pigments from rhodopsin.

Batch adsorption of chicken photoreceptor extract using Concanavalin-A Sepharose enables separation of rod and cone pigments and separation of cone pigments of different color sensitivity. In earlier work, column separations using the same adsorption medium, although effective, with high resolution, were slow, demanding and required many differential bleachings of column fractions for analysis. It is shown here that affinity separations can be performed in the batch adsorption mode to purify cattle, frog and chicken rhodopsin. These procedures are more rapid and much more convenient. An extract from the chicken retina can rapidly be separated into four fractions, including three highly enriched (80% or more) visual pigment fractions: (1) extraneous proteins, carotenoids and phospholipids; (2) short wavelength-sensitive pigments; (3) iodopsin; and (4) rhodopsin. While the resolution is not as great as that of the columns, the selectivity is sufficient to produce cone pigments, which are only slightly contaminated with rhodopsin and free of other proteins, either to experiment with directly or to enable heavier loading on high resolution columns. The method is adaptable both to highly labile pigments and to very small quantities, neither of which perform well in column separations.

Adsorption↗