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PubMed1977

Age-associated glycopeptide pigment in human costal cartilage.

Age-associated pigmentation of human costal cartilage is caused by the accumulation of a brown water-soluble substance which can be only be extracted after proteolytic disruption of the cartilage. After isolation by gel filtration and ion exchange chromatography, the compound was identified as an acid glycopeptide. In contrast to ochronotic pigment and an artificial pigment derived by oxidation of homogentistic acid in alkaline solution, the age-associated cartilage pigment was strongly fluorescent and did not form insoluble complexes with cetylpyridinium chloride. Moreover, age-associated cartilage pigment is alkali resistant, in contrast to the ochronotic pigment. The pigment differs from lipofuscin in being strongly hydrophilic and having no affinity for fat stains. The unidentified chromophore could not be separated from the glycopeptide molecule.

Adolescent↗

PubMed1984

Polymer networks in pigment and cholesterol gallstones assessed by equilibrium swelling and infrared spectroscopy.

Sixty-five gallstones were assessed for content of network polymer by equilibrium swelling and infrared spectroscopy. All types of pigment gallstones exhibited swelling in aqueous buffers, indicating network polymer content, but swelling was greatest in black pigment gallstones. Gallstones composed principally of cholesterol did not swell. Swelling increased with increasing pH values from 6 to 10.5, suggesting that titratable carboxyl side chains of the pigment were intact. Swelling increased in the presence of 10 mM ethylenediaminetetraacetic acid, indicating that calcium ions provided secondary crosslinks in the network. In all types of pigment gallstones, the equilibrium swelling ratio at the maximum (pH = 10.5) was correlated inversely with the proportion of intact vinyl groups in the pigment assessed by infrared spectroscopy. This suggests that pigment vinyl groups are consumed in forming the covalent crosslinks of the polymer network. A weaker direct correlation between equilibrium swelling ratio and the percentage of unmeasured residue in the gallstones suggested that this residue may also have contributed to the swelling. The high content of cross-linked network polymer in black pigment gallstones renders their therapeutic dissolution improbable by physicochemical means.

Biopolymers↗

PubMedDate not supplied

[Radioautographic study of the cellular proliferation of retinal pigment epithelium in axolotls].

The proliferative activity of the pigment epithelium cells in the axolotl eyes was studied using 3H-thymidine in two types experiments: after the removal of lens, iris and retina and upon the cultivation of the pigment epithelium pieces in the cavity of lens-less eye. Irrespective of the operation type, the level of proliferation of the pigment epithelium cells changed regularly with respect to the time of observation. In the intact eye, the level of proliferation of the pigment epithelium cells was not high: the index of labelled nuclei equaled 0.5%, no mitoses were found. The highest values of the index of labelled nuclei (12.6-32.1%) and of the mitotic index (0.54-1.07%) were registered on the 10-20th days after the operation. After 40 days, the indices of proliferative activity of the pigment epithelium cells approached gradually those for the intact eye. The cultivation of the pigment epithelium cells in the cavity of a lens-less eye for 50 days did not result in their transdifferentiation into retina cells. The layered retina found in 7.7% of cases after the removal of lens, iris and retina could regenerate either from the cells of the retina growth zone localized in the region of embryonic split, or due to transdifferentiation of the pigment epithelium cells.

Ambystoma mexicanum↗

PubMed1984

The macular pigment. II. Spatial distribution in primate retinas.

The spatial density distribution of macular pigment in primate retinas was described by two-wavelength microdensitometry of retinal sections. The macular pigment is most dense along the path of the receptor axons in the center of the fovea. Another band of high density is present in the inner plexiform layer in many retinas. The density in both fiber layers declines to low, relatively constant levels within 1 mm eccentricity. Both the total retinal density of macular pigment and the contributions of subsets of the retinal layers were estimated by integrating along the path of light traversing the retina from the vitreal surface to the outer segments. The integrated densities were measured at several eccentricities to establish the profile of macular pigment density along a diameter through the fovea. The macular pigment profile was unimodal in some cases and trimodal in others. The main central peak always occurred in the center of the fovea. The total retinal density of the central peak ranged from 0.42-1.0 absorbance. Most of the pigment is interposed between the outer segments and the stimulating light and is effective as a visual filter. The macular pigment is dichroic, with the major axis of absorption oriented tangential to a circle centered on the fovea. This is consistent with commonly accepted explanations of Haidinger 's brushes.

Animals↗

PubMed1982

[Cutaneous pigmentation caused by amiodarone. Optical and ultrastructural study].

Thirteen biopsies from 8 patients with amiodarone-induced skin pigmentation were studied. Light microscopy showed that skin pigmentation of these patients was produced by solar elastosis, increase of melanin and accumulation of the properly called amiodarone pigment in the upper dermis. The degree of solar elastosis and the amount of amiodarone pigment was related to total doses of amiodarone. This pigment was negative for fat stains and positive for Masson-Fontana stain, and had neither birrefringency nor autofluorescence. Ultrastructurally, the granules of amiodarone pigment appeared as membrane-bound granules with a fingerprint-like lamellated structure, which others have related to lipofuscin. We conclude, however, that this pigment may be a metabolite of amiodarone, morphologically and histochemically related to melanin.

Adult↗

PubMed1982

Experimental study on the drainage of so-called intravenous fat pigment from the liver. Long-term observation with histologic, enzyme-histochemical and electron microscopic analysis.

The drainage and decrease of so-called intravenous fat pigment (i.v. fat pigment), which was a lipoid-pigment complex and deposited in the reticuloendothelial system after repeated infusions of Intrafat (intravenous fat emulsion), was observed in the liver of the rabbit by histological, histochemical and electron microscopic methods. As a result, the i.v. fat pigment was mainly found in Kupffer cells immediately after the repeated injections of Intrafat. After then, depending on the period when no injection were given, it decreased gradually and disappeared finally from Kupffer cells. On the other hand, in the interstitium of Glisson's sheath, many phagocytes, extremely swollen and laden with i.v. fat pigment, appeared during the postinfusion period. Furthermore, these phagocytes laden with i.v. fat pigment were found in Glisson's sheath for a long period, although they showed a tendency of decrease. Histochemical and electron microscopic characteristics, quite similar to those of Kupffer cells, suggested that these phagocytes corresponded to the extremely swollen histiocytes or macrophages having some role in the drainage or the metabolism of the i.v. fat pigment.

Animals↗

PubMed1978

'Transdifferentiation' of chicken neural retina into lens and pigment epithelium in culture: controlling influences.

The in vitro transdifferentiation of chicken embryo neural retina into pigment epithelium and lens cells was investigated under a variety of experimental conditions. Our findings suggest that some aspects of the phenomena are a function of medium composition and volume, whereas others depend upon conditions which develop during culture growth. Before melanin is visible, potential pigment cells are recognized as foci within epithelial sheets which remain in contact with the dish. The final area occupied by colonies of potential pigment cells is directly proportional to bicarbonate concentration. Low total medium volume also favours formation of potential pigment cells. In contrast the extent of cells other than potential pigment cells is not related to bicarbonate and is favoured when the volume of medium is large. Accumulation of melanin within the potential pigment cell colonies is suppressed when cells are crowded together. Lentoid bodies are formed from cells which are distinct from potential pigment cells and arise in crowded situations, in association with multilayering. Another type of structure superficially resembling a lentoid is derived from cell aggregates formed during the initial establishment of cultures. The survival of these 'aggregate bodies' is inversely related to bicarbonate concentration. Crystallin content is unrelated to lentoid numbers. The results provide the basis for a new hypothesis concerning cytodifferentiation in this system.

Animals↗

PubMed1993

Visual pigment gene changes in adrenoleukodystrophy.

PURPOSE: The gene for X-linked adrenoleukodystrophy, a neurodegenerative disorder, is closely linked to the red/green color pigment genes on the distal X-chromosome Xq28 and one kindred is known to have a genetic change affecting both loci. The purpose of this article is to perform a systematic assessment of the frequency of this situation in many affected kindreds. METHODS: Recombinant DNA probes were used in blot hybridization studies to determine the structure of the color pigment genes in affected males from 59 different adrenoleukodystrophy kindreds. Whenever possible, color vision was measured using the Farnsworth 100-Hue test. RESULTS: Eleven of the 59 kindreds had abnormal color pigment gene clusters; these included fusion genes and changes in gene number. Only one kindred had a deletion of sequences immediately 5' to the color pigment genes. CONCLUSIONS: The incidence of color pigment gene changes in our 59 adrenoleukodystrophy kindreds is approximately twice the frequency of defective color vision reported in historic studies but is about the same as that found in studies of the actual genes in large populations. However, the range of changes in the color pigment genes in adrenoleukodystrophy is broader than encountered in most populations. Changes in the highly conserved color pigment genes reflect reorganizations in the Xq28 chromosomal region, some of which involve the contiguous gene for adrenoleukodystrophy.

Adrenoleukodystrophy↗

PubMed1993

Retinal pigment epithelial cell transplants in retinal degeneration slow mice do not rescue photoreceptor cells.

PURPOSE: To determine if retinal pigment epithelial cells are in any way involved in the degeneration of photoreceptor cells in the retinal dystrophy mouse model, retinal degeneration slow (rds); to determine if normal retinal pigment epithelial cell transplants can affect outer segment development in the retina. METHODS: Retinal pigment epithelial cells of neonatal normal pigmented C3H mice were isolated and transplanted into retinas of postnatal day 33 albino rds mice. Then eyes of 4-month-old rds mice, retinal pigment epithelial cell-transplanted and sham and non-treated control mice, were processed for light and electron microscopy and the thickness of the outer nuclear layer were measured and compared. RESULTS: Measurements of outer nuclear layer thickness in the transplant and control groups revealed that normal retinal pigment epithelial cell transplants did not cause photoreceptor cell rescue in rds mice. In addition, outer segments were not seen in retinal pigment epithelial cell-transplanted rds retinas. CONCLUSIONS: This study supports the conclusions of other investigators that the photoreceptor cell is the primary site of the genetic defect that results in retinal dystrophy in the rds mouse model.

Animals↗

PubMedDate not supplied

The LEC (Long-Evans Cinnamon) rat as an animal model for bilirubin-induced tooth pigmentation.

The LEC (Long-Evans Cinnamon) rat is well known as a useful animal model for hepatic disease. We noticed the green pigmentation in incisors 2-3 weeks after acute hepatitis accompanied by severe jaundice. This study was undertaken to elucidate the cause of this phenomenon. Half of the pigmented teeth were examined by histopathological analysis and microradiographic analysis. Pigmentation was observed as a green stripe that ran parallel to the incremental line in the dentine. The microradiographic analysis disclosed enhanced permeability of the pigmented area as compared with other areas. The rest of pigmented teeth were dried, powdered and bilirubin was extracted with chloroform /methanol/acetic acid, 30:10:0.5; v/v under sonication. After centrifugation, the supernatant was collected and evaporated. The residue was dissolved in chloroform and its absorption spectrum measured after diazo reaction to reveal the presence of bilirubin. The spectral characteristics indicated the presence of bilirubin in the pigmented teeth. Thus, the LEC rat may be useful animal model for bilirubin-induced tooth pigmentation.

Animals↗

PubMed1976

[Pigment formation and other biological properties of staphylococci].

A comparison was made of the pigment-forming capacity and the enzymatic activity, growth rate, virulence and sensitivity to antibiotics and egg lysozyme in 397 pigment, 203 pigment-free strains of staphylococci and 24 pigment-free Staph aureus mutants. Pigment formation did not always correlate with the general biological activity of the cultures, the rate of their growth and the sensitivity to antibiotics and lysozyme. Pigment-free staphylococcus mutants retained the principal properties of the initial strains (including the virulence and sensitivity to antibiotics and egg lysozyme) more frequently. It is supposed that the marker determining the pigment formation in staphylococci was not connected with the markers determining the most significant pathogenicity properties and also antibiotic resistance.

Drug Resistance, Microbial↗

PubMed1998

Intraepidermal bile pigment in skin biopsy specimens for graft-versus-host disease versus erythema multiforme.

The differentiation of graft-verus-host disease (GVHD) from erythema multiforme (EM) presents a common diagnostic challenge in skin biopsy specimens from patients who have received patients allogeneic bone marrow transplants. The presence of gastrointestinal involvement might be the only way to make a diagnosis of GVHD in these cases. In the absence of liver function tests, gastrointestinal biopsy, or molecular techniques such as microsatellite DNA analysis, the presence of intraepidermal bile pigment might prove helpful in elucidating hyperbilirubinemia and allowing a pathologist to favor a diagnosis of GVHD over EM. Routinely processed archival tissue from 50 cases of GVHD (42 Caucasian and 8 of unknown race) and 50 cases of EM (31 Caucasian and 19 of unknown race) was examined for pigmentation. Intraepidermal pigmentation was stained for bile pigment and melanin. Among the intraepidermal EM lesions, 4 (8%) stained for intracorneal melanin, but none stained for bile pigment. Among the intraepidermal GVHD lesions, 8 (16%) stained for intracorneal melanin, but 3 (6%) stained for intracorneal bile pigment. In addition, 13 (26%) GVHD lesions and 9 (18%) EM lesions showed melanosis with melanin in all layers of the epidermis as well as within papillary dermal melanophages. Thus, when presented with a differential diagnosis of GVHD versus EM, the presence of intraepidermal bile pigment might suggest liver involvement and a diagnosis of GVHD.

Bile Pigments↗

PubMed1956

The nature of the lamprey visual pigment.

From the retina of the land-locked population of the sea lamprey, Petromyzon marinus, a photolabile pigment was extracted which was identified spectrophotometrically as a member of the rhodopsin group of pigments. Using the absorption spectrum of a relatively pure solution and analysis by means of difference spectra, the peak of this pigment was placed at about 497 mmicro. The method of selective bleaching by light of different wave lengths revealed no significant amounts of any other pigment in the extracts. A similar pigment was also detected in retinal extracts of the Pacific Coast lamprey, Entospenus tridentatus. These results are significant for two reasons: (a) the lamprey is shown to be an example of an animal which spawns in fresh water but which is characterized by the presence of rhodopsin, rather than porphyropsin, in the retina; (b) the primitive phylogenetic position of the lamprey suggests that rhodopsin was the visual pigment of the original vertebrates.

Animals↗

PubMed1956

The nature of the gecko visual pigment.

Retinal extracts of the Australian gecko, Phyllurus milii (White), have revealed the presence of a photosensitive pigment, unusual for terrestrial animals, because of its absorption maximum at 524 mmicro. This pigment has an absorption spectrum which is identical in form with that of other visual chromoproteins. It is not a porphyropsin, for bleaching revealed the presence, not of retinene(2), but of retinene(1) as a chromophore. Photolabile pigments with characteristics similar to those of the Phyllurus visual pigment were also detected in retinal extracts of six other species of nocturnal geckos. The presence of this retinal chromoprotein adequately accounts for the unusual visual sensitivity curve described by Denton for the nocturnal gecko. This pigment may have special biological significance in terms of the unique phylogenetic position of geckos as living representatives of nocturnal animals which retain some of the characteristics of their diurnal ancestors. The occurrence of this retinene(1) pigment, intermediate in spectral position between rhodopsin and iodopsin, is interpreted in support of the transmutation theory of Walls. The results and interpretation of this investigation point up the fact that, from a phylogenetic point of view, too great an emphasis on the duplicity theory may serve to detract attention from the evolutionary history of the retina and the essential unitarianism of the visual cells.

Animals↗

PubMed1958

The photosensitive retinal pigments of fishes from relatively turbid coastal waters.

Digitonin extracts have been prepared from the retinae of a dozen species of marine and euryhaline teleost fishes from turbid water habitats. Spectrophotometric analysis of the extracts shows that the photosensitive retinal pigments of these species have maximum absorption above 500 mmicro. In nine species there are retinene(1) pigments with lambda(max) between 504 and 512 mmicro. In the marine but euryhaline mullet, Mugil cephalus, there is a porphyropsin with lambda(max) 520 mmicro. A mixture of rhodopsin and porphyropsin in an extract of a marine puffer, Sphoeroides annulatus, was disclosed by partial bleaching with colored light. In addition, one other species has a 508 mmicro pigment, of which the nature of the chromophore was not determined. The habitats in which these fishes live are relatively turbid, with the water greenish or yellowish in color. The spectral transmission of such waters is probably maximal between 520 and 570 mmicro. It is suggested that the fishes have become adapted to these conditions by small but significant shifts in spectral absorption of their retinal pigments. These pigments are decidedly more effective than rhodopsin in absorption of wavelengths above 500 mmicro. This offers a possible interpretation of the confusing array of retinal pigments described from marine and euryhaline fishes.

Fishes↗

PubMed1993

Clinical diagnosis of pigmented lesions using digital epiluminescence microscopy. Grading protocol and atlas.

BACKGROUND AND DESIGN: Epiluminescence microscopy (ELM) is a clinical technique that permits in vivo visual inspection of pigmented anatomic structures of the epidermis, dermoepidermal junction, and papillary dermis. A protocol is proposed for systematic visual inspection of pigmented lesions. Seventy pigmented lesions were imaged with a digital ELM camera system. Images were visually inspected for eight "global" ELM features, 23 "local" ELM features, and 18 network features. An atlas of the most clinically significant ELM features is presented with pilot estimates of their sensitivity and specificity for detecting melanoma. RESULTS: Preliminary data suggest that ELM features that may be most specific for melanoma include multicomponent pattern, nodular pattern, pseudopods, radial streaming, blue-gray areas, whitish veil (milky way), and sharp network margins. Epiluminescence microscopic features that may be most sensitive for melanoma include pigment dots, peripheral erythema, peripheral dark network patches, marked mean network irregularity, network line thickness variability, radial streaming, blue-gray areas, and whitish veil (milky way). Epiluminescence microscopic features that may be most sensitive for severe melanocyte atypia include pigment dots, peripheral erythema, hypopigmented network patches, peripheral dark network patches, marked mean network irregularity, and focal absence of network. In addition, features that may have a very high specificity for benign lesions include saccular pattern (suggests hemangioma), globular pattern (suggests a compound or dermal nevus), and multiple comedolike openings (suggests seborrheic keratosis). CONCLUSIONS: Features most sensitive for severe atypia and melanoma could form the basis for a screening test for considering biopsy. Features most specific for melanoma then could be applied to further triage management of pigmented lesions that meet initial screening criteria. In addition, features with very high specificity for benign lesions may help develop ELM criteria to avoid unnecessary surgery.

Atlases as Topic↗

PubMed1987

Whole eyes reconstituted from embryonic half anlagen: alterations in donor-derived territories in Xenopus pigment chimerae.

Grafts from pigmented donor embryonic eye rudiments into albino hosts were used to chart i) fates of local cell groups in three positions in whole eye rudiments, and ii) alterations in graft-derived territories when the posterior half of the rudiment was ablated. Small pigmented patches of graft-derived tissue were conspicuous in albino embryos and tadpoles, enabling us to directly monitor their location and size in the eyes of living animals. The three (right eye) positions marked by pigmented grafts were dorsal (12 o'clock), anterior (3 o'clock), and anteroventral (5 o'clock). Control transplants reared without secondary ablation produced black sector territories in pigment retinal epithelium and iris at corresponding 12 o'clock or 2 o'clock or 4 o'clock positions on the larval eyeball. In the experimental series posterior half-anlagen were ablated. The remaining anterior half-anlagen, each containing a pigmented graft, reconstituted spherical larval eyeballs of reduced size. During healing, donor-derived pigmented sector territories remained coherent, but were altered in position and size compared to controls. Dorsal cells (from 12 o'clock grafts) appeared to move rapidly along the newly formed cut edge into the wound and went on to form expanded black sectors in posterior eye regions. More gradually, sector territories of anterior cells (3 o'clock grafts) and anteroventral cells (5 o'clock grafts) shifted toward dorsal in a counterclockwise direction. Thus all three types of graft derived pigment territories were altered in eye anlage fragments as they healed to form half-size spherical eyes.

Animals↗

PubMed1988

Intraspinal pigmented schwannoma with malignant progression.

A case with recurrent pigmented intraspinal tumour with malignant progression is presented. The primary tumour grew around the nerve roots T9 and T10, was attached to dura and infiltrated the vertebral bone tissue. On light microscopy it was comprised of monomorphic cells with large amount of cytoplasmic pigment and many large pigmented globoid bodies. Mitoses were not observed. On electron microscopy, in addition to cytoplasmic melanosomes of regular size, macromelanosomes were numerous. The tumour cells were surrounded partially by basement membrane like material. On these bases a histological diagnosis of benign pigmented tumour of neural crest origin was suggested (a possible pigmented meningioma or pigmented schwannoma). The patient got a recurrence one year after the primary operation. Biopsy from the re-operation showed histologically the same type of tumour with more pleomorphic cells. Subsequently, the tumour grew progressively and metastases were observed in the lungs and in the skin. The patient died two years after the primary operation. The malignant progression of the tumour and other reports on similar tumours was most consistent with a diagnosis of malignant pigmented schwannoma and this was confirmed later on with immunohistochemical staining showing positive staining for basement membrane components, collagen type IV and laminin as well as a positive staining for S-100 protein. The present findings show that despite benign histological features these tumours can behave very aggressively and stress the need of more information on this type of tumour.

Female↗