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PubMed1988

High-performance liquid chromatography of carthamin, safflor yellow A and a precursor of carthamin. Application to the investigation of an unknown red pigment produced in cultured cells of safflower.

A reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed to analyse and purify carthamin, safflor yellow A (safflomin-A) and the yellow precursor of carthamin. A red pigment similar to carthamin was extracted from cell suspension cultures of safflower (Carthamus tinctorius L.) as an application of biotechnology. The RP-HPLC method was used to characterize the unknown red pigment. Various spectroscopic methods were used to characterize purified carthamin and the purified unknown pigment. Based on these spectral observations, it was concluded that the unknown red pigment produced in cultured cells of safflower differed from carthamin, although the unknown pigment might be a glycoside. From other observations, the possibility of anthocyanins and carotenoids were also discounted. It was assumed that the cultured cells lacked the biosynthetic pathway of the yellow precursor of carthamin, although they possessed the activity of the enzyme mediating the synthesis of carthamin from the yellow precursor.

Cells, Cultured↗
PubMed2001

Identification of lipid binders in paintings by gas chromatography. Influence of the pigments.

The influence of the presence and the type of pigments in the lipid binding media of paintings were studied by gas chromatography with flame ionization detector. The drying oils were linseed stand oil, poppy oil and sunflower oil, and the pigments studied were cadmium red, cobalt blue, tin white, lead white, chalk and plaster of Paris, commonly used in paintings. The results indicate that the stearic/palmitic ratio and the presence of pigments are quite stable during ageing. However, some differences in the oleic acid/palmitic acid ratio were found, depending on the type of pigment present in the lipid binding media. These variations are related to the drying effect of the pigments. The proposed method has been applied to the identification of drying oils in two samples from baroque paintings in the "Basilica de la Virgen de los Desamparados" of Valencia, Spain.

Art↗
PubMed2003

In vivo gene transfer of pigment epithelium-derived factor inhibits tumor growth in syngeneic murine models of thoracic malignancies.

OBJECTIVE: Pigment epithelium-derived factor is known to be an inhibitor of angiogenesis. We hypothesized that in vivo gene transfer of pigment epithelium-derived factor may inhibit tumor angiogenesis and growth in syngeneic models of thoracic malignancies. METHODS: An adenovirus vector encoding the human pigment epithelium-derived factor cDNA (AdPEDF) was used to transduce human lung cancer cells in vitro. Transgene expression was assessed using Western analysis. Three different murine flank tumors (2 lung, 1 colon) were then established in syngeneic mice and treated intratumorally with phosphate-buffered saline, AdPEDF, or an empty vector (AdNull). Endpoints measured included transgene expression, tumor size, and animal survival, as well as microvessel density within the tumor. Additionally, a murine pulmonary metastasis model was established by intravenous injection of a syngeneic colon adenocarcinoma cell line expressing a marker gene (beta-galactosidase). One day later, treatment (phosphate-buffered saline, AdNull, or AdPEDF) was administered intrapleurally. Tumor burden (gross and histologic inspection, lung weight, and beta-galactosidase expression) was then evaluated 13 days after vector dosing, and survival was recorded. RESULTS: AdPEDF-derived expression of pigment epithelium-derived factor was demonstrated in vitro and in vivo. In syngeneic murine lung cancer flank tumors, intratumoral administration of AdPEDF significantly inhibited tumor growth (P <.01), prolonged mouse survival (P <.01), and decreased microvessel density (P <.01) compared with control groups. In the pulmonary metastasis model, AdPEDF-treated mice exhibited significantly reduced lung lesions, lung weight (P <.0005), beta-galactosidase expression (P <.05), and animal survival was prolonged (P <.05). CONCLUSION: Gene transfer of pigment epithelium-derived factor suppresses tumor vascularization and growth, while prolonging survival in syngeneic murine models of thoracic malignancies.

Adenoviruses, Human↗
PubMed2002

Mechanism and clinical significance of prostaglandin-induced iris pigmentation.

The new glaucoma drugs latanoprost, isopropyl unoprostone, travoprost, and bimatoprost cause increased pigmentation of the iris in some patients. The purpose of the present article is to survey the available preclinical and clinical data on prostaglandin-induced iris pigmentation and to assess the phenomenon from a clinical perspective. Most of the data have been obtained with latanoprost, and it appears that there is a predisposition to latanoprost-induced iris pigmentation in individuals with hazel or heterochromic eye color. As latanoprost and travoprost are selective agonists for the prostaglandin F(2alpha) receptor, it is likely that the phenomenon is mediated by this receptor. Several studies indicate that latanoprost stimulates melanogenesis in iridial melanocytes, and transcription of the tyrosinase gene is upregulated. The safety aspects of latanoprost-induced iris pigmentation have been addressed in histopathologic studies, and no evidence of harmful consequences of the side effect has been found. Although a final assessment of the clinical significance of prostaglandin-induced iris pigmentation currently is impossible to make, it appears that the only clear-cut disadvantage is a potential heterochromia between the eyes in unilaterally treated patients because the heterochromia is likely to be permanent, or very slowly reversible.

Amides↗
PubMed1997

Visual pigments and oil droplets from six classes of photoreceptor in the retinas of birds.

Microspectrophotometric examination of the retinal photoreceptors of the budgerigar (shell parakeet), Melopsittacus undulatus (Psittaciformes) and the zebra finch, Taeniopygia guttata (Passeriformes), demonstrate the presence of four, spectrally distinct classes of single cone that contain visual pigments absorbing maximally at about 565, 507, 430-445 and 360-380 nm. The three longer-wave cone classes contain coloured oil droplets acting as long pass filters with cut-offs at about 570, 500-520 and 445 nm, respectively, whereas the ultraviolet-sensitive cones contain a transparent droplet. The two species possess double cones in which both members contain the long-wave-sensitive visual pigment, but only the principal member contains an oil droplet, with cut-off at about 420 nm. A survey of the cones of the pigeon, Columba livia (Columbiformes), confirms the presence of the three longer-wave classes of single cone, but also reveals the presence of a fourth class containing a visual pigment with maximum absorbance at about 409 nm, combined with a transparent droplet. No evidence was found for a fifth, ultraviolet-sensitive receptor. In the chicken, Gallus gallus (Galliformes), the cone class with a transparent droplet contains "chicken violet" with maximum absorbance at about 418 nm. The rods of all four species contain visual pigments that are spectrally similar, with maximum absorbance between about 506 and 509 nm. Noticeably, in any given species, the maximum absorbance of the rods is spectrally very similar to the maximum absorbance of the middle-wavelength-sensitive cone pigments.

Animals↗
PubMed1998

Pigment gene expression in protan color vision defects.

We screened 150 male eye donors and identified four who did not have or express L pigment genes, consistent with each of them having a congenital protan color vision defect. One donor was identified as a protanope because he had and expressed a single X-chromosome photopigment gene that encoded an M pigment. Three were categorized as protanomalous because each expressed significant levels of genes specifying two spectrally different M pigments. The first gene in each of the protanomalous arrays was expressed the most and encoded an M pigment that differed in amino acid sequence from M pigments in color normal men.

Base Sequence↗
PubMed1999

Visual pigments, cone oil droplets, ocular media and predicted spectral sensitivity in the domestic turkey (Meleagris gallopavo).

A microspectrophotometric survey conducted on the retinal photoreceptors of the domestic turkey (Meleagris gallopavo) revealed the presence of five different types of vitamin A1-based visual pigment (rhodopsin) in seven different types of photoreceptor. A single class of rod contained a medium wavelength-sensitive visual pigment (wavelength of maximum absorbance, lambda max, 504 nm). Four different types of single cone contained visual pigment maximally sensitive to wavelengths in either the long (LWS, lambda max 564 nm), medium (MWS, lambda max 505 nm), short (SWS, lambda max 460 nm) or violet (VS, lambda max 420 nm) spectral ranges. The LWS, MWS and SWS single cones contained pigmented oil droplets with cut-off wavelengths (lambda cut) at 514, 490 and 437 nm, respectively. The VS single cone contained a transparent oil droplet which displayed no significant absorbance above 330 nm. A single class of double cone was also identified, both the principal and accessory members of which contained the LWS cone visual pigment. The principal member contained an oil droplet with a lambda cut at 436 nm. No oil droplet was observed in the accessory member. The use of a glycerol-based cell mountant, which reduced wavelength dependent measurement artefacts in the microspectrophotometric measurements, is described. Predictions of cone effective spectral sensitivity, incorporating measurements of the spectral transmission of the ocular media, suggest that turkeys have considerable sensitivity to wavelengths in the ultraviolet-A (UV-A, 315-400 nm) spectral range. This has implications for both the visual ecology of wild birds and the welfare of intensively farmed individuals.

Animals↗
PubMed1987

Exogenous pigment in Peyer's patches.

Dark brown granular pigment was found consistently in macrophages in the deep aspect of adult Peyer's patches. Tissue sections from intestinal resections of 35 patients with a variety of pathologic diagnoses and of seven postmortem cases with no evidence of gastrointestinal disease were examined for the presence of this pigment. It was found in all patients over the age of 6 years (34 cases) but was not found in any children below that age (eight cases). Scanning electron microscopy with secondary and backscattered electron imaging and x-ray energy spectroscopy were performed on routine histologic sections. The pigmented macrophages contained aluminum and silicon, diffusely present throughout the cytoplasm, and numerous discrete foci of titanium. Pigment containing these same elements has also been found around dilated submucosal lymphatics, in mesenteric lymph nodes, and in some transmural inflammatory aggregates of Crohn's disease. The pigment probably is derived from the diet and actively taken up by Peyer's patches, which are able to incorporate inert particulate matter.

Aluminum↗
PubMed1993

Histopathologic findings in congenital grouped pigmentation of the retina.

BACKGROUND: Congenital grouped pigmentation of the retina is a condition characterized by multiple, well-circumscribed, flat, pigmented fundus lesions clustered in a fashion resembling "bear tracks." METHODS: Light and electron microscopy was used to study these lesions in an eye of a 2-year-old boy. The eye was enucleated for retinoblastoma. RESULTS: Similar to the classic, solitary, congenital hypertrophy of the retinal pigment epithelium (CHRPE), the involved RPE cells contained an increased number of large pigment granules. Unlike CHRPE, most pigment granules retained the normal ellipsoidal shape. In addition, hypertrophy and hyperplasia of the RPE cells were not significant features by light and electron microscopy. CONCLUSION: Although the lesions in this case superficially resembled CHRPE by light microscopy, ultrastructural differences were identified.

Child, Preschool↗
PubMed1993

Pathologic findings in the retinal pigment epitheliopathy associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam.

BACKGROUND: A pigment epitheliopathy that resembles ophthalmomyiasis interna occurs in approximately 10% of a large sample of the Chamorro population of Guam age 39 years or older; the rate is approximately 50% among those who have amyotrophic lateral sclerosis or Parkinsonism-dementia complex (lytico bodig). METHODS: Since publication of an earlier clinical report of affected patients, several of them have died of their neurologic disease, and their eyes were obtained for pathologic study. This is the first pathologic report of the retinal pigment epitheliopathy seen in the setting of amyotrophic lateral sclerosis/Parkinsonism-dementia complex of Guam and is based on examination of 13 eyes from 7 patients. RESULTS/CONCLUSION: Focal areas of attenuation of the retinal pigment epithelium in association with a reduced amount of intracellular pigment correlated with the funduscopic and gross appearance. No larvae were seen, and there was no evidence of inflammation. The pathogenesis of this pigment epitheliopathy remains undetermined.

Amyotrophic Lateral Sclerosis↗
PubMed1995

Choroidal hypoperfusion in acute posterior multifocal placoid pigment epitheliopathy. An indocyanine green angiography study.

BACKGROUND: The pathogenesis of acute posterior multifocal placoid pigment epitheliopathy remains obscure. The placoid lesions and characteristic findings on fluorescein angiography have been interpreted as representing either primary disease of the retinal pigment epithelium or disease of the choroidal vasculature. This study used indocyanine green (ICG) choroidal videoangiography to investigate this controversy. METHODS: Sequential choroidal videoangiography was performed with ICG and a scanning laser ophthalmoscope on patients with acute posterior multifocal placoid pigment epitheliopathy. Image analysis was used to differentiate between masking and ischemia as to the cause of hypofluorescence on the angiograms. RESULTS: Indocyanine green angiograms of acute posterior multifocal placoid pigment epitheliopathy showed areas of hypofluorescence in both the early and late pictures that correlated with the placoid lesions. Image analysis identified these as areas of choroidal hypoperfusion. Successive films showed partial or complete resolution of these hypofluorescent areas. CONCLUSIONS: Indocyanine green choroidal videoangiography has shown choroidal hypoperfusion to underlie the pathogenesis of acute posterior multifocal placoid pigment epitheliopathy.

Acute Disease↗
PubMed2004

[Posterior scleritis simulating acute posterior multifocal placoid pigment epitheliopathy].

INTRODUCTION: Posterior scleritis is a rare but probably underdiagnosed process. The lesions may cause diagnostic confusion with other diseases such as intraocular tumors and orbital or cerebral involvement. In the case presented, posterior scleritis simulated acute posterior multifocal placoid pigment epitheliopathy. CASE REPORT: A 43-year-old woman presented with a history of pain and eye redness with lid swelling in the left eye followed by visual deterioration. On fundus examination, there was disc and macular edema with multiple grayish-white placoid and deep chorioretinal lesions in the posterior pole. Fluorescein angiography was compatible with acute posterior multifocal placoid pigment epitheliopathy, but the inflammatory context was unusual in this disorder. An orbital computed tomographic scan and b-scan ultrasonography showed posterior scleral thickening and the diagnosis of posterior scleritis was made. Etiological investigations were negative. A pulse of corticosteroids was started and the patient's symptoms and signs improved on clinical and angiographic examination. DISCUSSION: Posterior scleritis may present with a range of clinical findings. Its clinical features may simulate many other diagnoses such as acute posterior multifocal placoid pigment epitheliopathy. Management is different in each situation: abstention in acute posterior multifocal placoid pigment epitheliopathy and a high dose of corticosteroids or even immunosuppressive therapy in posterior scleritis. CONCLUSION: This report shows that posterior scleritis must be evoked in patients with unilateral fundus appearance of acute posterior multifocal placoid pigment epitheliopathy associated with an inflammatory context. Ultrasonography or MRI must be carried out.

Adult↗
PubMed2005

[Pigment dispersion and Artisan implants: crystalline lens rise as a safety criterion].

PURPOSE: To validate the theoretical notion of a crystalline lens rise as a safety criterion for ARTISAN implants in order to prevent the development of pigment dispersion in the implanted eye. MATERIAL AND METHOD: Crystalline lens rise is defined by the distance between the crystalline lens's anterior pole and the horizontal plane joining the opposite iridocorneal recesses. We analyzed the biometric measurements of 87 eyes with an Artisan implant. A comparative analysis of the crystalline lens rise was carried out on the nine eyes having developed pigment dispersion and 78 eyes with no problems. Among the modern anterior segment imaging devices (Artemis, Scheimpflug photography, optical coherence tomography, radiology exploration, magnetic resonance imaging, TDM), an anterior chamber optical coherence tomography (AC-OCT) prototype was used. RESULTS: This working hypothesis was confirmed by this study: the crystalline lens rise must be considered as a new safety criterion for implanting Artisan phakic lenses. Indeed, the higher the crystalline lens's rise, the greater the risk of developing pigment dispersion in the pupil area. This complication is more frequent in hyperopes than in myopes. We can consider that there is little or no risk of pigment dispersion if the rise is below 600 microm; however, at 600 microm or greater, there is a 67% rate of pupillary pigment dispersion. In certain cases, when the implant was loosely fixed, there was no traction on the iris root. This is a complication that can be avoided or delayed. CONCLUSIONS: The crystalline lens rise must be part of new safety criteria to be taken into consideration when inserting an Artisan implant. This notion must also be applied to other types of phakic implants. The distance remaining between the crystalline lens rise and a 600-micromm theoretical safety level allows one to calculate a safety time interval.

Adolescent↗
PubMed2004

Photobleaching of photosynthetic pigments in spinach thylakoid membranes. Effect of temperature, oxygen and DCMU.

The time dependence of photobleaching of photosynthetic pigments under high light illumination of isolated spinach thylakoid membranes at 22 and 4 degrees C was investigated. At 22 degrees C, the bleaching at 678, 472 and 436 nm was prominent but lowering the temperature up to 4 degrees C during illumination prevented the pigments from bleaching almost completely. The accelerating effect on pigment photobleaching by the presence of 3-(3,4 dichlorophenyl)-1,1-dimethyl-urea)-(DCMU), a well-known inhibitor of the electron transport and known to prevent photosystem I (PSI) and photosystem II (PSII) against photoinhibitory damage, was also suppressed at low temperature. At 22 degrees C in the presence and absence of DCMU, the decrease of the absorption at 678 and 472 nm was accompanied by a shift to the shorter wavelengths. To check the involvement of reactive oxygen species in the process, pigment photobleaching was followed in anaerobiosis. The effects of the three different environmental factors--light, temperature and DCMU--on the dynamics of photobleaching are discussed in terms of different susceptibility of the main pigment-protein complexes to photoinhibition.

Aerobiosis↗
PubMed1992

Cellular autofluorescent pigment and interstitial fibrosis in smoker's lung.

The mechanisms by which cigarette smoking lead to bronchopulmonary diseases are incompletely understood. The most characteristic lesion is a chronic macrophage-alveolitis accompanied by slight fibrosis and emphysema. The macrophages contain a ceroid-like granular autofluorescent pigment in their lysosomes. Using immunohistochemical methods, open lung-, transbronchial biopsies and cells obtained by broncho-alveolar lavage from cigarette smokers were studied: anti-human macrophage serum and anti-human elastase, immune sera against type I, type III collagens and fibronectin were used in the demonstration of the cellular components of alveolitis and the connective tissue constituents of fibrosis. The characteristic red-brown autofluorescent pigment of the macrophages was also found in an extra-alveolar location mainly in peribronchial, septal and pleural scars. Similar emission colour occurred focally in the elastic laminae of fibrotic alveoli and sclerotic arteries. Granular fluorescent pigment was found in many bronchial epithelial cells. The epithelial pigmentation was associated with increased transcription of nucleic acid proteins, revealed by colloid silver (AgNOR) reaction. The results suggest that the autofluorescent pigment substances in macrophages may indicate or also play a role in the development of pathological connective tissue and epithelial changes of smoker's lung, in addition to the known mediators and enzymes.

Adult↗
PubMed1997

Quantitative differences in endolymphatic calcium and endocochlear potential between pigmented and albino guinea pigs.

A number of previous studies have suggested that melanin may play a role in Ca2+ homeostasis of endolymph. In the present study, endolymph Ca2+ levels and endocochlear potential (EP) were measured in all four cochlear turns of pigmented or albino guinea pigs. Auditory sensitivity was also evaluated using cochlear action potential (AP) thresholds. In pigmented animals we found that endolymph Ca2+ tended to increase from base to apex of the cochlea, while EP systematically decreased towards the apex. In contrast, no significant Ca2+ gradient was found in albinos and the EP decline was far less. As a result, the apical turn of albino animals had significantly lower Ca2+ and significantly higher EP than in pigmented animals. AP thresholds pooled across all test frequencies were significantly lower in albino animals although no differences at individual frequencies reached significance. Even after correction for EP differences, the endolymph Ca2+ levels in albino animals were significantly lower than in pigmented ones. These results confirm that there are significant physiologic differences between pigmented and albino animals, which are a likely consequence of the absence of melanin in the albino cochlea. They are consistent with the involvement of melanin in the active transport of Ca2+ into endolymph.

Acoustic Stimulation↗
PubMed1994

Localization of lysosomal enzymes in the retina and retinal pigment epithelium of RCS rats.

Using ultrahistochemical and immunohistochemical techniques, localization of acid phosphatase and cathepsin D was demonstrated in the retina and pigment epithelium of 1 to 42 day old RCS rats and its nonaffected congenic rat strain. Both enzymes are present in the pigment epithelium of the normal and dystrophic rat eye. As early as the age of 1 week, it was found that the lysosomes in the dystrophic rat retina are less stable in releasing acid phosphatase than those of control animals. Infiltration of cathepsin D into the subretinal space could first be detected with certainty in 2-week-old animals. The fragility of the lysosomal membrane and, therefore, the release of both enzymes became more pronounced as the animals aged. The findings of this study indicate that the instability of the lysosomal membrane in the RCS rat pigment epithelium may initiate degeneration of photoreceptors and pigment epithelium. The demonstration of cathepsin D activity has proved very helpful in revealing the physiological or pathophysiological condition of retinal pigment epithelium.

Acid Phosphatase↗
PubMed1995

The retinal pigmented epithelium is required for development and maintenance of the mouse neural retina.

BACKGROUND: During development of the vertebrate eye, there is a series of reciprocal cellular interactions that determine the fate of the eye components. Although evidence from organ culture suggests that the retinal pigmented epithelium (RPE) organizes the laminar structure of the differentiated neural retina, no role has been identified for the RPE in early eye development, nor has the later function of RPE been demonstrated in vivo. RESULTS: To investigate the role of RPE cells in eye development, we generated transgenic mice that carry the attenuated diphtheria toxin-A gene; this transgene was driven by the promoter of the gene encoding the tyrosinase-related protein-1, which is specifically expressed in pigment cells. Depending on the expression level of the transgene, the retinal epithelium was ablated before or after its differentiation into a pigmented cell layer. We show that an early ablation (embryonic day E10-11) resulted in disorganization of the retinal layer, immediate arrest of eye growth and subsequent eye resorption. A later ablation (E11.5-12.5) allowed the eye to be maintained during embryogenesis, but the laminar structure of the retina became disrupted by the end of gestation, the vitreous failed to accumulate the adults were anophthalmic or severely microphthalmic. In some microphthalmic eyes, a number of RPE cells escaped ablation and formed patches of pigmented cells; the laminar structure of the retina was maintained immediately adjacent to such pigmented areas but disrupted elsewhere. In both cases--early or late ablation of the RPE--the retina appears to be the primary affected tissue. CONCLUSIONS: We conclude that presence of the RPE is required for the normal development of the eye in vivo. Its presence early in development is necessary for the correct morphogenesis of the neural retina. After the neural retina has started to differentiate, the RPE is still necessary, either directly or indirectly, to maintain the organization of the retinal lamina.

Animals↗