Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PIGMENTATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed2002

Dermoscopic examination of nail pigmentation.

BACKGROUND: Diagnosis of longitudinal melanonychia is usually difficult, and neither a single clinical criterion nor a combination of symptoms currently can be used to clearly distinguish malignant from benign bandlike pigmented nail lesions. Biopsy is painful and often leaves definitive dystrophic scars. OBJECTIVES: To describe and evaluate dermoscopic patterns associated with longitudinal nail pigmentation. PATIENTS AND METHODS: A total of 148 unselected consecutive cases of longitudinal melanonychia were included over a period of 4 years (20 melanoma, 37 nevi, 16 drug-induced nail pigmentation, 45 nail apparatus lentigo of various types, 8 ethnic-type nail pigmentation, and 22 subungual hemorrhages). All patients were recruited from the dermatology unit outpatient clinic of the Hôtel Dieu de Lyon. All cases were photographed in vivo under oil immersion (dermoscopy). Patterns were recorded prior to final pathologic diagnosis. An independent biostatistics unit performed statistical evaluation using 7 semiologic patterns. RESULTS: Melanoma cases were significantly associated with a brown coloration of the background and the presence of irregular longitudinal lines (P =.001). Blood spots were mostly observed in subungual hemorrhages (P =.001); however, their presence could not rule out melanoma. Micro-Hutchinson sign was observed only in melanoma, but its rare occurrence did not allow any statistical evaluation of its specificity. Nail apparatus nevi were significantly associated with a brown coloration of the background and the presence of regular lines (P =.001). Nail apparatus lentigo, ethnic-type pigmentation, and drug-induced pigmentation were significantly associated with homogeneous longitudinal thin gray lines and gray coloration of the background (P =.001). Microscopic longitudinal grooves were unspecific, occurred in several conditions, and were associated with any type of ungual discoloration. CONCLUSIONS: We believe that dermoscopic examination of the nail plate in cases of longitudinal melanonychia provides useful information that could help clinicians to more accurately decide if a nail apparatus biopsy should be performed; however, histopathologic diagnosis remains the gold standard in doubtful cases.

Adult↗
PubMed1997

A gene responsible for the pigment dispersion syndrome maps to chromosome 7q35-q36.

OBJECTIVES: To demonstrate the inheritance of the pigment dispersion syndrome in 4 families and to determine the location of a gene responsible for this syndrome. PATIENTS: Fifty-four members of 4 families affected by the pigment dispersion syndrome and pigmentary glaucoma. All 4 families are white. Two of the pedigrees are of Irish descent, and 2 are of mixed western European descent that includes some Irish ancestry. INTERVENTIONS: Individuals from 4 pedigrees affected by the pigment dispersion syndrome and their spouses were clinically examined for evidence of the pigment dispersion syndrome. DNA samples from patients and appropriate family members were used for a genome screen using microsatellite repeat markers distributed throughout the human genome. Genotypes were used for linkage analysis to identify markers segregating with the disease trait. RESULTS: Twenty-eight patients showed clinical evidence of the pigment dispersion syndrome. Of these, 14 also had elevated intraocular pressures requiring medical or surgical treatment or both. Significant linkage was observed between the disease phenotype and markers located on the telomere of the long arm of human chromosome 7 (i.e., 7q35-q36). The maximum 2-point lod score (i.e., Zmax) for a single pedigree (i.e., PDS5) was 5.72 at theta = 0 for markers D7S2546 and D7S550. An analysis of affected recombinant individuals demonstrated that the responsible gene is located in a 10-centimorgan interval between markers D7S2462 and D7S2423. CONCLUSIONS: The pigment dispersion syndrome was found to be inherited as an autosomal dominant trait in 4 affected pedigrees. The gene responsible for the syndrome in these 4 families maps to the telomeric end of the long arm of chromosome 7 (i.e., 7q35-q36). Locating a gene responsible for this condition is the first step toward the isolation of the gene itself. Characterization of the responsible gene will help elucidate the pathophysiology of this disease and potentially will lead to new methods of diagnosis and treatment.

Adolescent↗
PubMed1990

Localization of pigment cells in cultured frog skin.

The pigmentation pattern of ventral skin of the frog Rana esculenta consists mainly of melanophores and iridophores, rather than the three pigment cells (xanthophores, iridophores, and melanophores) which form typical dermal chromatophore units in dorsal skin. The present study deals with the precise localization and identification of the types of pigment cells in relation to their position in the dermal tracts of uncultured or cultured frog skins. Iridophores were observed by dark-field microscopy; both melanophores and iridophores were observed by transmission electron microscopy. In uncultured skins, three levels were distinguished in the dermal tracts connecting the subcutaneous tissue to the upper dermis. Melanophores and iridophores were localized in the upper openings of the tracts directed towards the superficial dermis (level 1). The tracts themselves formed level 2 and contained melanophores and a few iridophores. The inner openings of the tracts made up level 3 in which mainly iridophores were present. These latter openings faced the subcutaneous tissue In cultured skins, such pigment-cell distribution remained unchanged, except at level 2 of the tracts, where pigment cells were statistically more numerous; among these, mosaic pigment cells were sometimes observed.

Animals↗
PubMedDate not supplied

Gallbladder glycoprotein secretion in mice with hemolytic anemia and pigment gallstones.

The nb/nb mouse with hereditary hemolytic anemia provides an animal model for the study of pigment gallstone disease. We measured glycoprotein synthesis and secretion in gallbladder neck and fundus of 6-month-old mice without stones, and in 12-month old mice with and without stones in order to determine the effect of age and presence or absence of stones on mucin release. We observed that the gallbladder necks of 12-month-old nb/nb mice with pigment stones secreted more 3H-glucosamine-labeled glycoprotein (68.2 dpm per microgram protein) than did the gallbladder necks of mice without pigment stones (31.1 dpm per microgram protein). When expressed as a percentage of total glycoprotein synthesis in the gallbladder neck, secretion of glycoprotein was 23.4% in 6-month-old hemolytic mice and 28.7% in 12-month-old hemolytic mice without pigment stones. However, in the presence of pigment stones, the percentage of secreted glycoprotein rose to 4.08%, which differed significantly from both 6-month-old (p < 0.02) and 12-month-old mice without stones (p < 0.05). Our results suggest that the presence of gallstones in nb/nb mice was associated with a localized increase in glycoprotein release from gallbladder neck. The mechanism for this increase may be precipitation of pigment-mucin concentrations in the gallbladder neck glands which has been previously described in this animal model.

Aging↗
PubMed1982

Melanin-like pigment in the human prostate.

Twenty surgical specimens of prostate [1 histologically normal, 8 with benign hyperplasia (BPH), and 11 with cancer (PCa)] were examined by histochemical staining methods for the presence of a melanin-like pigment that we first observed in organ culture. Fontana-Masson-positive pigment was observed in epithelial cells of the normal specimen, of five BPH and of eight PCa. The distribution of pigment in BPH was unpredictable and patchy. The pigment was consistently absent in neoplastic epithelia. Silver-positive stromal cells also were observed in a number of the specimens. The epithelial pigment reacted to histochemical stains in part like melanin, in part like lipofuscin. It probably represents an endogenous pigment similar to other types of noncutaneous melanins.

Humans↗
PubMed1976

On the fine structure of the small, heavily pigmented non-pyramidal cells in lamina II and upper lamina III of the human isocortex.

With the aid of a newly developed technique for the successive examination of both the Golgi and pigment picture of individual neurons (Braak, 1974a) Braak (1974b) demonstrated that within lamina II and upper lamina III of the human isocortex, heavily pigmented non-pyramidal cells are distributed irregularly and sparsely. The lipofuscin pigment granules serve as excellent internal markers to identify these non-pyramidal cells in ultrathin sections. This favourable circumstance facilitates the study of these interneurons in the electron microscope. The heavily pigmented non-pyramidal cells are small, spherical to avoid with diameters of about 12-15 mum. One pole of the cell comprising a large cytoplasmic area gives rise to a few dendrites, while the other pole is occupied by the nucleus and in some cases is in close apposition to another nerve cell body. The nucleus is deeply invaginated by the large cytoplasmic area and occasionally displays nuclear inclusions. Among the usual organelles distributed within the large cytoplasmic area the mitochondria with a moderately electron dense matrix are abundant and the coarse lipofuscin pigment granules are the most striking elements. The latter contain densely packed filamentous or tubular material and a single vacuole. The perikaryon rarely receives more than 3 type I and type tii synapses per section per cell, whereas the dendrites receive numerous synapses of both type I and type II. Within the apposition zone to another nerve cell body (which in no case is a heavily pigmented non-pyramidal cell) puncta adhaerentia occur and also contacts in which the cleft of 8 nm is intersected by a dense stratum. Some of the ultrastructural findings are summarized in the schematic drawing of Figure 15.

Adult↗
PubMed1982

Optokinetic, vestibular, and optokinetic-vestibular responses in albino and pigmented rats.

Horizontal eye movements and neuronal activity in the vestibular nuclei and pretectum were recorded in albino and pigmented rats in response to optokinetic, vestibular (VS), combined visual-vestibular (VVS) sinusoidal stimulations. 1. VOR slow phase velocity in VS condition leads head velocity. This phase lead is smaller in albino than in pigmented rats. 2. Presence of vision (VVS) improves the phase angle of the VOR in both strains, especially at low frequencies. In pigmented rats the VOR is perfectly compensatory with respect to phase at all frequencies whereas in albinos the eye velocity still leads the head velocity. 3. There is no difference in the response characteristics of vestibular nuclear neurons (VN) to VS between albino and pigmented rats which could explain the difference in their VORs. 4. In the pigmented rat, there is a strong optokinetic input to VN which provokes a shift of the response peak towards peak head velocity. These visual-vestibular interactions at VN level are in agreement with the changes in the phase angle of the VOR. 5. In albino rat, there are no differences in the response characteristics of VN between VS and VVS, thus the decrease of the VOR phase lead observed in VVS compared to VS is due either to visual-vestibular interactions outside of the vestibular nuclei or to some general arousing effect of light. 6. Recording of responses of pretectal neurons to visual stimulation in albino rats has shown that they are activated in a phasic or tonic way by light on ("On cells") or off ("Off cells"). Contrary to the pigmented rat, pretreated neurons in albino exhibited no detectable direction specific optokinetic responses.

Animals↗
PubMed2001

In Situ Assessment on the Physiological State of Purple and Green Sulfur Bacteria through the Analyses of Pigment and 5S rRNA Content.

Time-depth distribution of the microbial anaerobic assemblage of Lake Cisó was analyzed by microscopy, pigment composition, and electrophoretic analysis of 5S rRNAs. Purple (Amoebobacter-like and Thiocystis minor-like cells) and green (Chlorobium-like) sulfur bacteria were very abundant. Both groups coexisted in depth and in time despite the fact that they compete for the same natural resources (e.g., light and sulfide). Cell abundance, group-specific pigment content, and group-specific 5S rRNA content did not change in parallel with depth. This was due to variations in the specific content of both RNA and pigments. Specific content of RNA was systematically higher in purple than in green sulfur bacteria. The latter, in turn, displayed a much higher pigment content. Specific content of both RNA and pigments changed with depth and time. Analysis of tRNA band patterns indicated no changes in the populations forming the assemblage. Changes in specific contents, therefore, were the result of physiological adaptations of the populations already present in the system. We concluded that each group of bacteria showed differential adaptations in both RNA and pigment content, and that the specific contents measured were good indicators of the physiological status of these bacteria in situ. The higher content of RNA in purple sulfur bacteria indicates that these organisms are the main contributors to anaerobic carbon fixation and sulfide oxidation processes in Lake Cisó.

Journal Article↗
PubMedDate not supplied

A prospective study of iridial pigmentation and eyelash changes due to ophthalmic treatment with latanoprost.

PURPOSE: To conduct a 12-month prospective study on the occurrence of latanoprost-induced iridial pigmentation and eyelash change in Japanese patients with glaucoma METHODS: Seventy-five patients (75 eyes) were enrolled in the study. Photographs of the iris and eyelashes were taken under identical conditions before and after treatment. Three glaucoma specialists assessed the iridial pigmentation/eyelash change independently with no knowledge of patient data. The effects of age, sex, concomitant medication, and type of glaucoma on iridial pigmentation/eyelash change were investigated, and intraocular pressure (IOP) reduction and iridocorneal angle pigmentation before and after latanoprost treatment were compared between patients with iridial pigmentation/eyelash change and patients without these changes. RESULTS: The incidence of iridial pigmentation was 6.3% at 1 month, 15.7% at 3 months, 37.8% at 6 months, and 56.5% at 12 months. The incidence of eyelash change was 0% at 1 month, 33.8% at 3 months, 44.4% at 6 months, and 46.2% at 12 months. Latanoprost did not affect IOP reduction or iridocorneal angle pigmentation. No significant relationship between iridial pigmentation and eyelash change was observed. None of the investigated parameters except age affected the iridial pigmentation/eyelash change. CONCLUSION: Iridial pigmentation and eyelash change occurred at a high frequency in long-term treatment with latanoprost in Japanese glaucoma patients.

Adult↗
PubMed1989

Determination and regulation in the pigment cell lineage of the ascidian embryo.

The brain of the ascidian larva comprises two pigment cells, termed the ocellus melanocyte and the otolith melanocyte. Cell lineage analysis has shown that the two bilateral pigment lineage cells (a-line blastomeres) in the animal hemisphere give rise to these melanocytes in a complementary manner. The results of the present investigation suggest that the specification of the fate of pigment cells proceeds in two distinct steps. First, the determination of pigment lineage cells requires an inductive interaction from the vegetal blastomeres of the A-line. Cell dissociation experiments demonstrated that the inductive interaction is completed by the midgastrula stage. However, the two bilaterally positioned cells destined to become the pigment cells in the first step are still equipotent at this stage in that they can give rise to either the ocellus or otolith. Thus, they constitute what is termed an "equivalence group." In the second step, the individual fates of the two cells that compose the equivalence group are determined. Namely, one cell develops into an ocellus and the other cell develops into an otolith. Photoablation of one of the pigment precursor cells at various stages indicated that the second step of determination occurs at the midtailbud stage. It is suggested that the cue to choose one of the alternative developmental pathways may be positional information that exists along the anteroposterior axis. The second step of determination is thought to be mediated by a hierarchical interaction. In the absence of this interaction, melanocyte specification proceeds along the dominant pathway that results in the differentiation of an ocellus.

Animals↗
PubMed1988

4-Hydroxyretinal, a new visual pigment chromophore found in the bioluminescent squid, Watasenia scintillans.

The bioluminescent squid, Watasenia scintillans has three visual pigments. The major pigment, based on retinal (lambda max 484 nm), is distributed over the whole retina. Another pigment based on 3-dehydroretinal (lambda max approximately 500 nm) and the third pigment (lambda max approximately 470 nm) are localized in the specific area of the ventral retina just receiving the downwelling light. Visual pigment was extracted and purified from the dissected retina. The chromophores were then extracted and analyzed with HPLC, NMR, infrared and mass spectroscopy, being compared with the synthetic 4-hydroxyretinal. A new retinal derivative, 11-cis-4-hydroxyretinal, is identified as the chromophore of the third visual pigment of the squid.

Animals↗
PubMed2006

Reflectance confocal microscopy of pigmented basal cell carcinoma.

BACKGROUND: Reflectance confocal microscopy (RCM) is a high-resolution imaging tool for in vivo noninvasive evaluation of skin lesions. OBJECTIVE: We sought to describe the relevant RCM features for pigmented basal cell carcinoma (BCC). METHODS: Pigmented skin lesions with a differential diagnosis of pigmented BCC were imaged using dermoscopy and RCM, followed by excision for histologic analysis. RESULTS: RCM demonstrated aggregations of tightly packed cells with palisading, forming cordlike structures and nodules with irregular borders and variable brightness; these represented nests of pigmented basaloid tumor cells on histopathology, and blue-gray ovoid areas on dermoscopy. These tumor nests were associated with bright dendritic structures, identified histologically as either melanocytes or Langerhans cells, together with numerous bright oval to stellate-shaped structures with indistinct borders representing melanophages, and with highly refractile granules of melanin. LIMITATIONS: The pigmented BCCs imaged in this study were predominantly nodular; a different set or additional criteria may be necessary for detection of infiltrative and metatypical BCCs. CONCLUSION: RCM may permit in vivo diagnosis of pigmented BCC.

Aged↗
PubMed2004

Oral mucosal pigmentation secondary to minocycline therapy: report of two cases and a review of the literature.

Minocycline is a semisynthetic broad-spectrum antimicrobial agent that was first introduced into clinical practice in 1967. The most common use of minocycline is for the long-term treatment of acne vulgaris. A well-recognized side effect of minocycline treatment is pigmentation, which has been reported in multiple tissues and fluids including thyroid, skin, nail beds, sclera, bone, and teeth. While there have been several reports of oral pigmentation following minocycline therapy, these have been, for the most part, pigmentation of the underlying bone with the overlying oral mucosa only appearing pigmented. We report two cases of actual pigmented oral mucosal lesions on the hard palate secondary to minocycline therapy with the accompanying histopathology, followed by a discussion of minocycline-induced oral pigmentation and a differential diagnosis of these lesions.

Adult↗
PubMed2001

Pigmented conjunctival squamous cell carcinoma simulating a conjunctival melanoma.

PURPOSE: To report a pigmented conjunctival squamous cell carcinoma that clinically simulated a conjunctival melanoma. DESIGN: Interventional case report. METHODS: Ocular examination, surgical excision, and clinicopathologic correlation. RESULTS: A 78-year-old white man developed a lightly pigmented mass at the temporal limbus of his right eye. The differential diagnosis included pigmented squamous cell carcinoma and malignant melanoma. Histopathologic examination revealed a malignant squamous cell tumor that contained foci of melanin pigment. The final diagnosis was pigmented conjunctival squamous cell carcinoma. CONCLUSION: Conjunctival squamous cell carcinoma may rarely be pigmented and simulate a conjunctival melanoma.

Aged↗
PubMed2000

Kinetic analysis of red pigment and citrinin production by Monascus ruber as a function of organic acid accumulation.

In submerged cultures performed in synthetic medium containing glucose and glutamate, the filamentous fungus Monascus ruber produced a red pigment and a mycotoxin, citrinin. In oxygen-limiting conditions, the production of these two metabolites was growth-associated, as was the production of primary metabolites. In oxygen-excess conditions, the profile of citrinin production was typical of a secondary metabolite, since it was produced mostly during the stationary phase. In contrast, the production of the pigment decreased rapidly throughout the culture, showing a profile characteristic of an inhibitory mechanism. The organic acids produced during the culture, L-malate and succinate, were shown to be slightly inhibitory against pigment production, while citrinin production was unaffected. However, this inhibition could not account for the observed profile of pigment production in batch cultures. Other dicarboxylic acids such as fumarate or tartrate showed a similar effect to that provoked by malate and succinate as regards pigment production. It was concluded that the decrease in red pigment production during the culture was due to the inhibitory effect of an unknown product whose accumulation was favored in aerobic conditions.

Journal Article↗
PubMed1985

Pigmented free-floating vitreous cysts in two young adults. Electron microscopic observations.

Pigmented free-floating vitreous cysts were observed in two young adults. In both patients, the cyst was in the visual axis; however, the size and extent of pigmentation of the cyst wall compromised the visual acuity only in case 1. In this case, the vitreous cyst was aspirated through the pars plana and studied by light and electron microscopy. Histopathologically, the cyst was lined by a heavily pigmented layer of cuboidal cells intermixed with sheets of nonpigmented cells forming papillae. Ultrastructurally, the pigmented cells contained predominantly large, mature melanosomes (0.9-2.2 micron). Scattered immature melanosomes with a scarcity of mitochondria and other cytoplasmic organelles were present. Additionally, the cells were invested by a thin polarized basement membrane and displayed apical microvilli. Numerous microvillous processes were noted under the plasmalemmae and between adjacent cells. The results of the light and ultrastructural studies provide support for the hypothesis that the cyst in case 1 originated from the pigment epithelium. The possibility of a traumatic etiology is proposed for these pigmented vitreous cysts. If significant visual impairment is present, surgical removal of the cyst through a pars plana approach can be safely performed as in our case 1.

Adult↗
PubMed1999

Dowling-Degos disease (reticulate pigmented anomaly of the flexures): a clinical and histopathologic study of 6 cases.

BACKGROUND: Few case series describing Dowling-Degos disease (DDD) have been reported. OBJECTIVE: Our purpose was to review the clinical and histopathologic findings in DDD. METHODS: We reviewed the clinical and histopathologic findings in 6 patients with DDD who were evaluated at the Mayo Clinic. RESULTS: In addition to the typical flexural pigmented reticulate macules, comedo-like lesions on the back or neck or both were present in all 6 patients; 3 patients had pitted perioral scars, and 3 patients reported pruritus of affected flexural areas. Five patients were female, 5 patients had onset of pigmentation before age 24 years, and 3 patients had a family history of DDD. One patient had additional pigmentation involving the dorsum of the hands and proximal nailfolds and fingernail dystrophy. Histopathologically, pigmented rete ridge elongation with thinning of suprapapillary epithelium, dermal melanosis, and perivascular lymphohistiocytic infiltration were consistently observed. CONCLUSION: Comedo-like lesions, pruritus, and pitted perioral scars are common features in association with the reticulate flexural pigmentation. Histopathologically, pigmented rete ridge elongation and dermal melanosis of biopsy specimens from flexural areas are seen.

Adolescent↗
PubMed2003

Microthrombectomy reduces postsclerotherapy pigmentation: multicenter randomized trial.

OBJECTIVE: Postsclerotherapy pigmentation occurs in nearly 30% of patients. Hemosiderin, from degradation of the venous thrombus, is the possible cause. The hypothesis that early removal of the thrombus may eliminate or decrease the incidence of pigmentation has not been proved or documented. The objective of this study was to investigate the effects of early microthrombectomy on incidence of postsclerotherapy pigmentation. MATERIAL AND METHODS: This multicenter, randomized, controlled study involved 101 patients with varicose veins (100 women, 1 man; mean age, 46 years [range, 25-68 years]). Patients were divided into two groups, with veins 1 mm or less in diameter (group 1, n = 50) or veins 3 mm or less in diameter (group 2, n = 51). Group 1 was treated with Sotradecol (STD) 0.25%, and group 2 with STD 0.50%. In each patient, an area of varicosities was selected and divided into halves. One half was randomized to microthrombectomy and the other half served as control. Microthrombectomy was performed 1 to 3 weeks after treatment in the randomized half. Standard photographs were obtained before and 16 weeks after treatment, and were evaluated by three independent reviewers who were blinded to treatment assignments. Each reviewer received an identical set of pretreatment and posttreatment 10 x 15-cm color photographs of the study area, and completed a scoring sheet. Average of the scores was used to evaluate primary (pigmentation) and secondary (overall clinical improvement) end points. The paired t test and chi-square test were used for statistical analysis. RESULTS: In group 1, microthrombectomized areas had statistically significant less pigmentation (P =.0047) and better overall clinical improvement scores (P =.0002) compared with the control side. In group 2 there was no significant difference between the two areas, but patients reported significant relief of pain and inflammation associated with postsclerotherapy thrombophlebitis. CONCLUSION: In veins 1 mm or smaller, microthrombectomy reduced pigmentation and improved overall clinical results. In veins 3 mm or smaller, statistical significance was not achieved, but thrombectomy resulted in faster resolution of the postsclerotherapy pain and inflammation. On the basis of these results, microthrombectomy after sclerotherapy is recommended.

Adult↗