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PubMed1982

Distribution and significance of norepinephrine in the lateral cochlear wall of pigmented and albino rats.

Picogram quantities of norepinephrine were found in cochlear regions of pigmented and non-pigmented rats. These regions of the cochlea were the modiolus, organ of Corti--osseous spiral lamina and the lateral cochlear wall. The content of norepinephrine in the modiolus and lateral cochlear wall of the pigmented rat was significantly greater than that in areas of the non-pigmented rat. In contrast, there was no statistical difference between the norepinephrine content of the organ of Corti--osseous spiral lamina region of the pigmented rat and that of the albino rat. Since a major difference between the pigmented and albino rats is the presence of melanin-containing melanocytes in the modiolus and lateral cochlear wall region of the pigmented animals, it is possible that norepinephrine is stored in cochlear melanocytes.

Animals↗

PubMed1993

Turn-specific differences in the endocochlear potential between albino and pigmented guinea pigs.

Recent findings indicate that structural differences exist in the stria vascularis (SV) between albino and pigmented guinea pigs. In the higher cochlear turns, volume density for marginal cells in the albino SV is abnormally large, while that for intermediate cells (melanocytes) is abnormally small. These anatomical variations suggest that functional differences between albino and pigmented inner ears also may be found. To examine this possibility, four strains of guinea pigs were studied, consisting of Hartley albino (N = 9) and NIH outbred pigmented (N = 15) guinea pigs, as well as albino (N = 11) and pigmented (N = 15) guinea pig siblings born to mixed litters. Tracheotomy and carotid artery cannulation were performed. Animals were mechanically ventilated, with periodic samples drawn for arterial blood gas analysis. Blood pressure, heart rate and rectal temperature were monitored. Compound action potentials were measured first to assess cochlear viability. Positive endocochlear potentials (+EP) then were recorded, beginning with the fourth turn, followed by the first, second and third turns. Results showed that the +EP in albinos remained relatively constant across cochlear turns, but decreased significantly from base to apex in the pigmented inner ears. Across all animals, mean +EPs (mV +/- S.E.M.) for turns 1-4 in albinos were: 72.5 (2.5), 68.7 (2.3), 59.2 (2.7), 68.1 (3.3); pigmented values were: 72.9 (2.9), 66.9 (2.6), 53.8 (3.0), 57.0 (2.7). One-way ANOVAs did not show a significant difference in albino +EPs between any of the cochlear turns, but did indicate a highly significant difference between turns in the pigmented inner ears (P < 0.000004). Post hoc comparisons demonstrated +EPs in turns 3 and 4 were smaller than in turn 1. Since turn 3 was recorded last in these experiments, and was reduced in value relative to turn 4 in both groups, it is likely that cochlear deterioration contributed to this result more than any other factor. These results, combined with previous anatomical data, indicate that a diminution of melanocyte cell volume in the albino SV is accompanied by an increase in marginal cell volume density and larger +EPs in the higher cochlear turns, at least at resting levels.

Albinism↗

PubMed1986

Opioid potentiated chromatophorotropin regulation of pigment migration in the land crab Gecarcinus lateralis.

In Gecarcinus lateralis dopamine treatment results in dispersion of black and concentration of red pigments within chromatophores. These effects of dopamine on the migration of pigments can be blocked by the dopamine antagonist haloperidol. These results strongly indicate the presence of a dopamine receptor mediated system in this organism. Serotonin injections also result in the dispersion of black pigment; however, this effect cannot be blocked by haloperidol. Norepinephrine was found to be without effect on this pigment regulatory system. Injections of crude eyestalk extract results in pigment migration within the chromatophores in both stalked and destalked animals. Injection of the stable methionine enkephalin analog FK 33 824 into the organisms causes no observable effects on the pigment system. However, coinjection with eyestalk extract strongly potentiates the effect of the extract. This potentiation can be completely blocked by the opiate antagonist naloxone, thus indicating that an endogenous opioid system may be part of the overall regulation of pigmentation movement.

Animals↗

PubMed2004

Trypan blue induces apoptosis in human retinal pigment epithelial cells.

PURPOSE: To examine whether trypan blue dye induces apoptosis in human retinal pigment epithelium cells. DESIGN: Laboratory investigation. METHODS: Pure cultures of human retinal pigment epithelium cells were isolated. The cells were incubated with different concentrations of trypan blue (0.5%, 0.10%, and 0.05%) for either 5 or 30 minutes. The rate of retinal pigment epithelium cell apoptosis was assessed with Annexin V-PE staining and flow cytometry. RESULTS: Trypan blue induced a statistically significant amount of apoptosis in retinal pigment epithelium cells at all the concentrations (0.5%, 0.10%, and 0.05%) (P <.05). The increase in incubation time (from 5 to 30 minutes) led to an increase in the number of apoptotic retinal pigment epithelium cells. CONCLUSION: The incubation of retinal pigment epithelium cells with trypan blue increased the number of apoptotic retinal pigment epithelium cells in vitro. Our results suggest that decisions regarding the intravitreal application of trypan blue dye need to be made with caution.

Annexin A5↗

PubMed2005

Pigmented-membrane formation on acrylic intraocular lenses after phacoemulsification.

PURPOSE: To report the formation of pigmented membranes on acrylic intraocular lenses (IOLs) after phacoemulsification and to determine the clinical characteristics of these pigmented membranes. DESIGN: Observational case series. METHODS: Four eyes of three patients were found to have pigmented membranes on their acrylic IOLs (Sensar AR40). Their medical records were reviewed. RESULTS: The pigmented membranes were observed at 4- to 9-month intervals after phacoemulsification. Their best-corrected Snellen visual acuity (BCVA) decreased by more than 2 lines, ranging from 20/63 to 20/40. After Nd:YAG laser treatment, BCVA improved 2 to 4 lines. At 5- to 12-week intervals after Nd:YAG laser treatment, recurrences of the pigmented membranes were observed with decreased BCVA. CONCLUSIONS: We have observed visually significant, recurrent, pigmented membrane formation in eyes implanted with Sensar AR40 acrylic IOLs. To the best of our knowledge, pigmented membranes on acrylic IOLs have not been described previously.

Acrylic Resins↗

PubMed2005

Grouped congenital hypertrophy of the retinal pigment epithelium follows developmental patterns of pigmentary mosaicism.

PURPOSE: To determine whether sectorial-oriented grouped pigmentations of the retina follow developmental patterns of pigmentary mosaicism. DESIGN: Systematic literature review. PARTICIPANTS: Fundus images from patients with grouped congenital hypertrophy of the retinal pigment epithelium (CHRPE). METHODS: An extensive Internet and library search was performed to obtain articles dealing with grouped CHRPE. Each article was carefully screened for fundus images and inclusion criteria. Fundus images of sufficient quality were scanned, digitized, and matched in size using Adobe Photo Shop to compare the pattern location and extension of the pigmented lesion. These obtained patterns of grouped CHRPE were than mapped and superimposed. RESULTS: Forty-five images were retrieved from 32 articles with grouped CHRPE. The lesions extended from the margin of the optic disc and radiated in sectors to the fundus periphery. The stream of growth did not follow the pattern of the retinal nerve fiber layer, because the clusters of pigmented cells crossed the midline raphe not sparing the macular area. Smaller lesion clusters were mainly located near the optic disc, whereas larger lesions were found in the periphery. CONCLUSIONS: The growth pattern of grouped CHRPE is similar to cutaneous sectorial pigmentations. We speculate that pigmentary mosaicisms may be a modified wild-type allele in a somatic cell clone during early embryogenesis following developmental lines analogous to the cutaneous lines of Blaschko. The sectorial pigmentations on the ocular fundus may reflect the stream, outgrowth, and migration of retinal pigment epithelium cells during embryogenesis.

Humans↗

PubMed2005

Combining HPLC pigment markers and ecological similarity indices to assess phytoplankton community structure: an environmental tool for eutrophication?

A new tool combining the use of HPLC pigment markers with ecological similarity indices, to provide a fast and effective environmental tool for monitoring water quality, was investigated. HPLC pigment concentrations from a 4-year time series data set (2000-2003) from the western English Channel were used to calculate six similarity indices to assess changes in phytoplankton community structure. Indices obtained from HPLC data were compared with those produced from the corresponding phytoplankton biomass derived from microscopic analysis. Multivariate RELATE analyses (P<0.001) suggested that there was little loss of information when species biomass data were grouped into higher taxonomic levels, thereby providing justification for the use of pigment markers. To test the proposed methodology, product moment (r) and Spearman's rank (r(s)) correlation analyses were performed. Highly significant correlations (P<0.01, Canberra Metric: P<0.05) between percentage similarities derived from phytoplankton class biomass and pigment markers were found for all indices when data were pooled (n=104). A Mann-Whitney U-test suggested that indices were more sensitive to changes in relative biomass than pigment concentrations; however, pigment data also produced statistically significant findings (P<0.05). Combining HPLC pigment markers and ecological similarity indices to assess phytoplankton community structure has advantages over microscopy in that it is rapid, reproducible and better suited to large-scale environmental monitoring. We present a basic protocol for implementing this new tool using a suite of similarity indices into environmental monitoring of phytoplankton communities.

Chromatography, High Pressure Liquid↗

PubMed2001

Retinal pigment epithelial cell transplantation after subfoveal membranectomy in age-related macular degeneration: clinicopathologic correlation.

PURPOSE: To report the histopathology after retinal pigment epithelial cell transplantation and subfoveal membranectomy in age-related macular degeneration. METHODS: An 85-year-old white woman with bilateral choroidal neovascularization underwent subfoveal membranectomy combined with transplantation of a sheet of human adult retinal pigment epithelium (retinal pigment epithelium) under the foveal center in the right eye. The patient was immunosuppressed postoperatively with prednisone, cyclosporine, and azathioprine. The patient died from congestive heart failure 114 days after surgery. RESULTS: A patch of hyperpigmentation was visible at the transplant site under the foveola after surgery. Mound-like clusters of individual round, large densely pigmented cells were present in the subretinal space and outer retina in this area. There was loss of the photoreceptor outer segments and native retinal pigment epithelium in the center of the transplant bed, with disruption of the outer nuclear layer predominantly over regions of multilayered pigmented cells. Cystic spaces were present in the inner and outer retina. A residual intra-Bruchs membrane component of the original choroidal neovascular complex was present under the transplant site. CONCLUSIONS: The transplant site contained clusters of round, pigmented cells that did not form a uniform monolayer in most areas. The morphology at the transplant site is consistent with the lack of visual improvement seen after surgery in this patient.

Aged↗

PubMed2001

Local cellular sources of apolipoprotein E in the human retina and retinal pigmented epithelium: implications for the process of drusen formation.

PURPOSE: The inheritance of specific apolipoprotein E allelles has been linked to atherosclerosis, Alzheimer disease, and, most recently, to the incidence of age-related macular degeneration. Apolipoprotein E is a common component of the extracellular plaques and deposits characteristic of these disorders, including drusen, which are a hallmark of age-related macular degeneration. Accordingly, we assessed the potential biosynthetic contribution of local ocular cell types to the apolipoprotein E found in drusen. METHODS: We measured apolipoprotein E mRNA levels in human donor tissues using a quantitative assay of apolipoprotein E transcription, and we localized apolipoprotein E protein to specific cell types and compartments in the neural retina, retinal pigmented epithelium, and choroid using laser scanning confocal immunofluorescence microscopy. RESULTS: Apolipoprotein E immunoreactivity is associated with photoreceptor outer segments, the retinal ganglion cell layer, the retinal pigmented epithelium basal cytoplasm and basal lamina, and with both collagenous layers of Bruch membrane. Apolipoprotein E appears to be a ubiquitous component of drusen, irrespective of clinical phenotype. It also accumulates in the cytoplasm of a subpopulation of retinal pigmented epithelial cells, many of which overlie or flank drusen. Mean levels of apolipoprotein E mRNA in the adult human retina are 45% and 150% of the levels measured in liver and adult brain, the two most abundant biosynthetic sources of apolipoprotein E. Apolipoprotein E mRNA levels are highest in the inner retina, and lowest in the outer retina where photoreceptors predominate. Significant levels of apolipoprotein E mRNA are also present in the retinal pigmented epithelium/choroid complex and in cultured human retinal pigmented epithelial cells. CONCLUSIONS: Apolipoprotein E protein is strategically located at the same anatomic locus where drusen are situated, and the retinal pigmented epithelium is the most likely local biosynthetic source of apolipoprotein E at that location. Age-related alteration of lipoprotein biosynthesis and/or processing at the level of the retinal pigmented epithelium and/or Bruch membrane may be a significant contributing factor in drusen formation and age-related macular degeneration pathogenesis.

Adult↗

PubMed1994

Experimental transplantation of human retinal pigment epithelial cells on collagen substrates.

We studied the use of human retinal pigment epithelial cells cultured on a collagen support as a potential transplantation therapy to replace diseased or damaged retinal pigment epithelium. Using a transvitreal approach, we transplanted human retinal pigment epithelial cells attached to either a sheet of noncross-linked or cross-linked type I collagen into the subretinal space of New Zealand white rabbits, whose eyes lack pigment. Animals were killed after six weeks, and the eyes were fixed for light microscopy. The results demonstrated that, in eyes receiving the noncross-linked collagen support, a layer of pigmented donor retinal pigment epithelium was visible within the subretinal space, with a normal-appearing retina and no evidence of proliferative vitreoretinopathy or graft rejection. We believe this method may be applicable to replace dysfunctional retinal pigment epithelial cells in humans.

Animals↗

PubMed1990

Cloning of cDNA and amino acid sequence of one of chicken cone visual pigments.

The chicken has four kinds of color visual pigments, in addition to rhodopsin. A chicken genomic DNA library was screened with cDNA of human red-sensitive pigment and a chicken genomic DNA fragment including rhodopsin exons 2, 3 and 4, and then a genomic DNA fragment encoding a visual pigment, possibly an iodopsin, was cloned. A cDNA library, constructed from chicken retina mRNA, was screened with the genomic DNA fragment and the cDNA of human red-sensitive pigment, and the cDNA encoding the pigment was cloned. The nucleotide sequence of this cDNA was similar to that of the human red-sensitive pigment, with identities of 78% for the nucleotide sequence and 84% for the amino acid sequence with human red-sensitive pigment.

Amino Acid Sequence↗

PubMed1984

Arrest of pigment granule motion in erythrophores by quick-freezing.

We report the use of quick-freezing, as an alternative to conventional chemical fixation, to arrest the movement of pigment granules at various stages of the dispersion-aggregation cycle in Holocentrus erythrophores. During pigment aggregation, the granules in these cells move at up to 20 microns/sec, hence the structural changes underlying the movement are likely to be too fleeting to be captured faithfully by conventional aldehyde fixation. On the other hand, quick-frozen cells, when examined by freeze-etch electron microscopy, provide novel views of certain cytoplasmic components which appear to be involved in pigment granule movement, namely, fine (2- to 6-nm diameter) fibrils which link the granules to each other and to the radial array of microtubules. These fine crosslinking fibrils can be distinguished from thicker (8- to 15-nm diameter) strands of coherent granular material which pervade the cytoplasm of pigment-dispersed as well as pigment-aggregated cells. This granular matrix is removed by detergent permeabilization, after which it becomes apparent that the fine fibrils are insoluble and are distributed both within and distal to the aggregated pigment mass. The diameter of the specific fibrils does not change during pigment motion, which indicates that they are not contractile.

Animals↗

PubMed1984

Visual pigments and environmental light.

The visual pigments in the rods do not have a special absorption that gives them maximal sensitivity. The visual pigments of "deep sea" fish are an exception for these do match the environmental light to give maximum sensitivity. At the low light intensities at which the rods operate, it is the number of photons that go to make up each element of the image that limits the ability of the eye to discriminate detail and contrast. Chemically induced isomerisation of the visual pigment molecule may cause spurious visual signals that limit the ability of the eye to detect contrasts in very dim light. In bright light the spurious visual signals become insignificant in number compared to the true photon-induced visual signals. Compared to the rods, cone visual pigments do match the spectral properties of the environment except that there appear to be no visual pigments with an absorption maximum beyond the 625 nm porphyropsins in cones. U.V. absorbing pigments are know in invertebrates, birds and fish that live in very shallow water. Animals have photoreceptors in parts of the body other than the eyes. In vertebrates these sites include the pineal, chromatophores, brain, skin and harderian gland. There is evidence based on immunocytochemistry and action spectra that at least some of the skin and pineal receptors contain visual pigments, but like those of the rods, these do not match the spectral quality of the environmental light.

Animals↗

PubMed1995

The attenuation of blue-on-yellow perimetry by the macular pigment.

PURPOSE: To determine the influence of macular pigment absorption on blue-on-yellow perimetry using a technique suitable for application with the Humphrey Field Analyzer. METHODS: The sample comprised one eye from each of 46 healthy subjects (age range, 20-80 years). Macular pigment absorption was assessed by measuring medium-wavelength sensitive cone sensitivity for 460- and 570-nm narrowband stimuli at the fovea, at 5.5 degrees and at 8 degrees eccentricity. The differences in sensitivities recorded between the fovea and 8 degrees eccentricity and between 5.5 degrees and 8 degrees eccentricity for the 460-nm stimulus relative to a value of zero at 570 nm were attributed to absorption by the macular pigment. Blue-on-yellow perimetry was undertaken using a 460-nm narrowband blue Goldmann size V stimulus and a yellow 330-cdm-2 background. RESULTS: Group macular pigment absorption (mean +/- standard error) was 0.40 +/- 0.03 log units foveally and 0.00 +/- 0.03 log units at 5.5 degrees eccentricity. The group mean foveal macular pigment absorption was significantly different from zero (P < 0.01). The coefficient of repeatability for the macular pigment absorption procedure (based on test-retest data for 16 subjects) was +/- 0.28 log units at the fovea and +/- 0.35 log units at 5.5 degrees eccentricity. CONCLUSION: The net effect of ocular media and macular pigment absorption relative to 460 nm was to attenuate the blue-on-yellow visual field at the fovea by approximately 0.80 log units and elsewhere by 0.40 log units.

Absorption↗

PubMed1998

Pigment producing yeasts involved in the brown surface discoloration of ewes' cheese.

The appearance of a brown surface discoloration on Portuguese ewes' cheese has never previously been reported on. The regular occurrence of this defect over the past few years has caused serious financial losses to producers, which has led to growing interest in its study. This paper describes a preliminary approach to the problem, based on the hypothesis that pigment producing yeasts are involved. From a group of 51 yeast strains isolated from a number of brown cheese rinds, it was possible to distinguish four pigment producing groups: group I (12 strains), produced an extracellular brown pigment from tyrosine and alkalised the tested media; group II (21 strains), produced a diffusible, reddish-brown pigment from resorcinol and alkalised the tested media; group III (three strains), alkalised the tested media without producing any pigments; group IV (15 strains), neither produced pigments nor alkalised the media. Yarrowia lipolytica and Candida catenulata type strains were also tested and their behaviour was similar to the strains in groups I and IV, respectively. The Filobasidiella neoformans type strain was distinct from all the other groups. The identification methods used for some strains in groups I, II and III suggest that Yarrowia lipolytica species is common to all strains in group I, and that Debaryomyces hansenii is present in both groups II and III. A study of the effect of several metal ions on the production of the brown pigment from tyrosine indicated Mn2+ to be a strong activator. Evidence is provided suggesting that the browning process may be related to tyrosine Yarrowia lipolytica metabolism.

Alkalies↗

PubMed2003

Biliary pronucleating proteins and apolipoprotein E in cholesterol and pigment stone patients.

BACKGROUND/AIMS: Although cholesterol gallstone patients exhibit higher biliary cholesterol saturation than pigment stone patients, underlying mechanisms that affect stone type are unknown. We hypothesized that pronucleating proteins, hydrophobic bile salts or apolipoprotein E genotype affect stone type. We therefore compared these putative factors in cholesterol and pigment stone patients. METHODS: In 74 cholesterol and 12 pigment stone patients, bile lipids, various pronucleating proteins, crystallization and apolipoprotein E genotype were determined. RESULTS: Crystallization was enhanced, and cholesterol saturation higher in case of cholesterol stones, without any difference in bile salt composition. Concentrations of mucin (0.91+/-0.08 versus 0.31+/-0.06 mg/ml: P<0.0001), protein, IgM, IgG, IgA, haptoglobin, alpha1-acid glycoprotein and haptoglobin were 2-6-fold higher in cholesterol stone patients. Twenty cholesterol stone pts (27%) but only one pigment stone pt (8%) had at least one epsilon4 allele. There was a significant difference in allele frequencies between both groups (cholesterol stones similar to Dutch population: epsilon2 0.074, epsilon3 0.770, epsilon4 0.156: pigment stones: epsilon2 0.250, epsilon3 0.708, epsilon4 0.042). CONCLUSIONS: Various pronucleating biliary proteins are markedly higher in cholesterol than pigment stone patients. Also, apolipoprotein E genotype differs between cholesterol and pigment stone patients. These factors may affect gallstone type.

Adult↗

PubMed1982

Lipofuscin pigment accumulation in human brain during aging.

Histopathologic and autofluorescence investigations were carried out to study lipofuscin pigment accumulation in various age groups of human beings died in accidents (in 100 cases ranging from 1-70 years-of-age). Lipofuscin pigment granules were first observed to appear at 9 years of age. Qualitative studies revealed a progressive increase in the intracellular lipofuscin pigment accumulation with advancing age. These pigment granules were found to congregate in mass in nerve cells of old individuals. An increase in the lipofuscin pigment accumulation and decrease of Nissl substance was observed during aging. The percentage of pigmented nerve cells and the percentage of cytoplasmic area occupied by lipofuscin pigment granules increased significantly with the advancement of age.

Adolescent↗

PubMed1998

Occurrence of pigment precipitates after small incision cataract surgery.

PURPOSE: To assess the incidence of pigment precipitates and potential association with glaucoma, diabetes, and/or intraocular lens (IOL) optic center thickness in patients having small incision cataract surgery and foldable IOL implantation. SETTING: Eye Care Physicians of Michigan, Jackson, Michigan, USA. METHODS: A retrospective data analysis was conducted of patients with a preoperative diagnosis of glaucoma or diabetes or in whom pigment precipitates had been reported after cataract surgery. Group 1 consisted of 23 patients in whom pigment precipitates had been reported and Group 2, 92 patients in whom no precipitates were reported. Two statistical models were used to analyze preoperative, demographic, surgical, and postoperative variables and determine potential correlations. An overall incidence of the occurrence of pigment precipitates was calculated based on the total number of patients with foldable IOLs. RESULTS: The incidence of pigment precipitates was 0.35% (n = 23/6519). Mean time to occurrence was 5.5 months. No between-group differences were found in pathologies or other demographics or postoperative variables. Intraocular lens size and implantation correlated with the occurrence of pigment precipitates. CONCLUSION: The development of pigment precipitates after foldable IOL implantation did not appear to be affected by the presence of glaucoma or diabetes. Newer, slimmer IOL styles and refined insertion techniques were associated with a lower occurrence of precipitates.

Aged↗