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.

SourceResearch connectionFrom yearThrough year

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

At least 1,747 records · Page 97Linked to original sources

PubMed1975

Interactions of plasma retinol-binding protein with its receptor. Specific binding of bovine and human retinol-binding protein to pigment epithelium cells from bovine eyes.

Bovine and human retinol-retinol-binding protein (RBP) were iodinated to high specific activity. At least 34% of the iodinated material was native and retained its retinol chromophore as judged by its characteristic ability to bind to plasma prealbumin. Bovine and human retinol-125I-RBP were found to bind specifically to intact isolated pigment epithelium cells from bovine eyes. The specific binding was complete in about 1 min with an estimated second order rate constant of about 10-8 M-minus 1 S-minus 1 (at 22 degrees). The specific binding was temperature dependent with the binding at 0 degrees being some 7-fold slower than at 22 degrees. The specific binding of both human and bovine retinol-125I-RBP was a linear function of the number of binding sites (number of cells) and was saturable with respect to retinol-125I-RBP. Bound iodinated retinol-RBP was rapidly displaced by the addition of unlabeled retinol-RBP, indicating that the specific binding process was a surface phenomenon and was not due to endocytosis. At saturation about 3.7 to 5.2 times 10-4 molecules of either bovine or human retinol-125I-RBP bound to one bovine pigment epithelium cell. The dissociation constant for the binding between retinol-125I-RBP and pigment epithelium receptor was estimated to be about 5 times 10-minus 12 M. Addition of human prealbumin (thyroxine-binding prealbumin) did not affect the binding of either human or bovine retinol-125I-RBP to pigment epithelium cells. Retinol-125I-RBP did not bind specifically to isolated bovine rod photoreceptor outer segments. Human apo-RBP was less effective in displacing bound retinol-125I-RBP than either native or reconstituted human retinol-RBP. These results suggest a mechanism whereby, after delivering its retinol to the cell, apo-RBP is displaced from the specific receptor on pigment epithelium cell by another retinol-RBP molecule. This postulated mechanism makes it possible to control the delivery of retinol to the target cell by the relative plasma concentrations of apo- and retinol-RBP and their relative affinities for the specific receptor binding site.

Animals↗

PubMed2000

[Tyrosine metabolism, antioxidative system and free radical lipid oxidative processes in children with pigmented nevus and melanoma].

The plasma levels of tyrosine and the lipid peroxidation intermediate malonic dialdehyde (MDA) were measured in children with pigmental nevus and melanoma. They were found to have antioxidative protective failure. The presence of pigmental nevus predetermines the high incidence of tyrosine metabolic abnormalities. In children with pigmental nevus and melanoma, there was an impairment in the correlation of the parameters of tyrosine metabolism, the rate of free radical lipid peroxidation processes, and the status of the antioxidative system. The findings suggest that children with pigmental nevus may be referred to as a high cancer risk group and monitoring of these parameters should be recommended at follow-up of pigmental nevi.

Antioxidants↗

PubMed2000

Radiosynovectomy in pigmented villonodular synovitis.

BACKGROUND: Pigmented villonodular synovitis (PVS) is a very rare disorder characterized by a slowly progressive benign proliferation of synovial tissue. As yet, the mainstay of its treatment has been surgical or athroscopic synovectomy. However, the relapse rates reported are relatively high, ranging between 8% and 46%. The aim of this study was to evaluate the efficacy of a combined treatment with radiosynovectomy (RS) and surgical synovectomy. METHOD: We studied the effect of thirteen radiosynovectomies performed in eleven pigmented villonodular synovitis patients with Y-90 citrate or Re-186 sulfide. All patients had undergone intraarticular radiation therapy within 6 months after surgical synovectomy. Eight patients suffered from pigmented villonodular synovitis in the knee, the remaining three from pigmented villonodular synovitis in the hip. Two of eleven patients had to be treated twice, due to a relapse of symptoms occurring four months after the first treatment. Therapy responses were evaluated one year after the initial radiosynovectomy. Clinical response was assessed on three-point rating scales evaluating the degree of hydrops, rubor, and motility as well as the degree of pain, these four parameters were then averaged to an overall clinical score (CS). We also quantified the relative uptake of Tc-99m-diphosphonate in the joint involved on the blood pool (BUR) and delayed images (DUR). RESULTS: Clinical score decreased from 5.45 +/- 1.04 to 1.18 +/- 1.16 at one year after treatment (p < 0.005), and the blood pool from 0.51 +/- 0.36 to 0.08 +/- 0.44 (p < 0.005). Delayed images were not significantly changed: 0.66 +/- 0.71 versus 0.66 +/- 0.73 (p = 0.3). CONCLUSION: A combination of surgical synovectomy with radiosynovectomy is highly efficacious in treating clinical symptoms of pigmented villonodular synovitis. It also improves bone scintigraphic signs of inflammation, but has no influence on late diphosphonate uptake.

Adult↗

PubMed2000

Focal, flat pigmentations of the oral mucosa: a clinical approach to the differential diagnosis.

The purpose of this article is to assist the clinician in establishing a clinical approach to the diagnosis of focal, flat pigmentations of the oral mucosa. These pigmentations include lesions that may be blue, purple, red, black, or brown. The etiopathogenesis may be variable and the pigment may originate from an exogenous (extrinsic) or endogenous (intrinsic) source. Exogenous pigmentations are of a traumatic or iatrogenic origin. Intrinsic pigmentations are either vascular or melanocytic. Clinical approaches include a thorough history and physical exam coupled with diascopy (blanchability), radiographs, and tissue examination (biopsies). An algorithm is presented to clarify the diagnostic approach. The diagnosis may vary from pathologic entities that require no treatment to others that may involve malignancies and their associated management. It is therefore extremely important that these lesions are identified and properly managed in an expeditious manner.

Algorithms↗

PubMed2001

[Large hairy pigmented spots in neurofibromatosis type 1: an atypical form of neurofibromas].

INTRODUCTION: Large hairy pigmented spots have been observed in patients with neurofibromatosis type 1. In this study we tried to determine the nature and the frequency of these hairy pigmented spots in neurofibromatosis type 1. PATIENTS AND METHODS: In patients with neurofibromatosis type 1, hairy pigmented spots with a diameter more than 3 cm were systematically notified. Realisation of the biopsy of the spot was proposed to the patient. RESULTS: Among 614 patients with neurofibromatosis type 1, seven (1.1 p. 100) had a large hairy pigmented spot. Biopsy was realized in six cases. In five cases, diagnosis was superficial and plexiform neurofibroma, the 6(th) case was a Becker's nevus. CONCLUSION: Large hairy pigmented spot is a rare aspect of superficial and plexiform neurofibroma during neurofibromatosis type 1. A biopsy may be useful if it is necessary for the disorder diagnosis.

Adolescent↗

PubMed2001

[An epidemiologic examination on the prevalence of the periodontal diseases and oral pigmentation in Yusho patients in 2000].

An epidemiologic examination was carried out to reveal the prevalence of the periodontal diseases and oral pigmentation in patients with Yusho in 2000. The results obtained were as follows. 1) 63 patients out of 69 patients with Yusho, who were measured periodontal pocket depth according to Ramfjord' methods, had at least one tooth with periodontal pocket deeper than 3 mm. Similarly, 188 teeth out of a total 285 examined teeth showed periodontal pocket with more than 3 mm depth. 2) In this examination, intraoral sinus tracts stoma were observed in 9 patients out of 70 patients. Radiographic examination and probing examination of pocket depth indicated that periapical lesions were involved in these intraoral sinus tract formation. 3) Oral pigmentation was observed in 46 out of 76 patients with Yusho. In this study, gingival pigmentation was most predominant among oral pigmentation. These results indicated that PCBs had yet affected the mechanism of oral pigmentation and metabolism of alveolar bone.

Adult↗

PubMed2001

[Intra-bleb pigmentation after phacoemulsification].

CASE REPORT: We report the finding of an intense intra-bleb pigmentation 24 hours after uncomplicated phacoemulsification in an eye with previous trabeculectomy. In the follow-up, considerable reduction in degree of pigmentation was observed and intraocular pressure remained under control without medication. DISCUSSION: Intra-bleb pigmentation after trabeculectomy or phacotrabeculectomy has been recently reported by Wanichwecharungruang; however it has never been mentioned after isolated phacoemulsification. It is usually related with intraoperative pigment dispersion. A preexisting thin bleb provides a clear view of intra-bleb pigmentation, that appears associated with a successful filtration.

Aged↗

PubMedDate not supplied

[Chemical study of "Penicillium" and "Trichoderma" pigments (author's transl)].

The green pigments from the fungi of the genera Trichoderma and Penicillium were partially extracted with formic acid. After two acid and one alkaline hydrolysis, the pigments of Trichoderma viride and Trichoderma koningii were sufficiently purified to undertake the chemical studies. The elemental and functional analyses, the U. V. and visible spectra and the chromatographic observations showed that these pigments are polyphenolic in nature. Gel filtration on Sephadex G50 suggested, on the one hand, the homogeneity of the pigment of T. viride and, on the other, the heterogeneity of the pigment of T. koningii.

Chromatography, Gel↗

PubMed1975

[Pigment glaucoma. Scanning-electronmicroscopic findings. (author's transl)].

In case of a patient suffering from pigment glaucoma trabeculectomy was performed on both eyes. In one trabecular section the outer wall of Schlemm's canal, and in the other the trabecular framework were investigated by scanning-electronmicroscopy. The intertrabecular spaces were largely blocked by pigment granula, which, in some places, were stored in the clump cells of the iris. Even the outer wall of Schlemm's canal was dotted with pigment granula. The scanning-electronmicroscopic findings revealed the pigmental drainage blocking of the aqueous humour and explained the acute pressure rise in the pigment glaucoma with wide iridocorneal angle by an acute obstruction of the already largely blocked intertrabecular spaces.

Adult↗

PubMed1975

[Changes in the liver transport of bile pigments in certain forms of jaundice under the influence of novobiocin and luminal].

The novobiocin and luminal test application increases the possibilities to differentiate premicrosome from postmicrosome jaundice and extends the knowledge on hyperbilirubinemia pathobiochemistry. Novobiocin (an antibiotic) inhibits the conjugation and glucuronidizing of bile pigments. Accordingly, the novobiocin test is strongly positive in any premicrosome jaundice form--Gilberts's disease, posthepatitis hyperbilirubinemia (PHHB) and hemolytic jaundice. It is negative in hepatocellular and hepatocanalicular jaundice, and in Dubin-Johnson's syndrome. In premicrosome jaundice with fluctuating bilirubinemia and normal bilirubin level at the time of examination, the novobiocin test may bring about manifestation of a latent or temporary compensated defect which proves to be most helpful in diagnosing. It is assumed that hemolytic jaundice is caused, apart from bile pigments hyperproduction, also by concomitant disorders in the intrahepatal transport of bile pigments. The latter hypothesis is corroborated by the data of the study. The luminal test is likewise markedly positive in premicrosome jaundice, and negative--in chronic hepatocellular and hepatocanalicular jaundice. In some instances with slight defect in the intrahepatal transport of pigments, the luminal test accounts for normalization of bilirubinemia and of the direct to total bilirubin ratio. The test is moderately positive in the syndrome of Dubin-Johnson. The latter fact supports the hypothesis that luminal, alongside the effect on transport mechanisms, exerts influence on bile pigments excretion also.

Bile↗

PubMed2002

Transgenic expression of IGF-1 modifies the proliferative potential of human retinal pigment epithelial cells.

PURPOSE: To induce the expression of insulin-like growth factor (IGF)-1, by using gene transfer methods, to modify the growth characteristics of human retinal pigment epithelial cells. METHODS: Human retinal pigment epithelial cells were transfected in vitro with plasmid vector pcDNA:IGF-1, which encodes an epitope-tagged human IGF-1 fusion protein and a selectable neomycin resistance gene. Transduced cells were cloned in G418 and expanded for analysis of IGF-1 transgene expression and its effect on the cell phenotype. The expression of the IGF-1 transgene in cloned cells was confirmed by reverse transcription-polymerase chain reaction and quantified by Western blot analysis. The growth characteristics of transduced clones were compared with the control by spectrophotometric and flow cytometric cell proliferation assays. RESULTS: Cloned retinal pigment epithelial cells expressed the IGF-1 transgene and secreted the IGF-1 fusion protein into the tissue culture medium. Transduced clones demonstrated a dose-dependent, enhanced ability to proliferate in low serum conditions, compared with the control. Clones that expressed moderate and high levels of the IGF-1 fusion protein were isolated and grew at a significantly faster rate and showed a statistically significant increase in the number of cells after 6 days, compared with the control (P < 0.002, paired samples, t-test). Expression of the IGF-1 transgene in synchronized clones enhanced cell cycle kinetics by increasing recruitment of the G(0)-G(1)-phase cells into the proliferative phase of the cell cycle. CONCLUSIONS: The human IGF-1 fusion protein encoded by the pcDNA:IGF-1 vector demonstrates paracrine biological activity in human retinal pigment epithelial cells in vitro. Expression and secretion of the IGF-1 transgene enhances growth characteristics in a dose-dependent manner and can modulate the proliferative potential of the retinal pigment epithelial cell.

Blotting, Western↗

PubMed2002

[Effects of tea polyphenols and tea pigments on cell cycle of HepG2 cells].

The effects of tea polyphenols and tea pigments on cell cycle of hepatic cancer cells were studied. HepG2 cells were incubated with 50 and 100 mg/L tea polyphenols and tea pigments for 48 h respectively. Flow cytometry, Western blot and RT-PCR analysis were used. Flow cytometry analysis showed that tea polyphenols and tea pigments induced G1 arrest. Western blot analysis showed tea polyphenols and tea pigments significantly inhibited the expression of cyclin D1 protein and induced higher expression of P21WAFI/CIPI protein. The result of RT-PCR analysis demonstrated that Cdk4 was significantly inhibited by tea polyphenols and tea pigments. It is concluded that the induction of cell cycle arrest may be an important mechanism of tea on cancer prevention.

Carcinoma, Hepatocellular↗

PubMed2000

[The cultivation, freezing-state preservation and resuscitation of human iris pigment epithelial cells in vitro].

PURPOSE: To establish the culture of human iris pigment epithelial cells in vitro and study the freezing-state preservation and resusciation. METHODS: The iris pigment epithelial specimens from human eyes were cultured in vitro. Based on the cell-frozen principle, the cultured cells were collected, then frozen in liquid nitrogen and resuscitation. RESULTS: Cultured iris pigment epithelial cells were obtained. Under the inverted light microscope, primary cells appeared multigonal and arranged in monolayer, there were abundant pigment granules in the cytoplasm and the nuclei each of which contained 1 or 2 nuceoli wre relatively transparent. Under the transmission electron microscope, there were plenty of microvilli at the cell membrane and desmosomes present in the intercellular space. 6 groups of cells were frozen. The resuscitation exeriment was carried out for 4 times, every times being successful. All of the resuscitated rates were more than 90%. CONCLUSION: The human iris pigment epithelial cells were cultured in vitro successfully, they can also be frozen and resuscitated, which will be useful in studies of pathogenesis for some eye disease.

Cells, Cultured↗

PubMed1999

[Inhibitory effects of tea polyphenols and tea pigments on liver precancerous lesions in rats].

A liver precancerous model in rats was established with diethylnitorsamine(DEN) injected intraperitoneally as initiator and promoted by partial hepatectomy and injection of CCl4. The model was used to study the chemopreventive effect of tea polyphenols and tea pigments. A water solution of 0.1% tea polyphenols or tea pigments was given to Wistar rats as drinking water during the 56-day experiment period. A stable and sensitive early marker of liver cancer--GST-Pi positive foci or nodule was measured by a immunohistochemical method. Both tea polyphenols and tea pigments decreased the density and area of the GST-Pi foci. The expression of GST-Pi mRNA in chemical induced precancerous liver tissue was measured by Northern Blotting technique, and the expression of GST-Pi isoenzyme in liver tissue was detected by Western Blotting method. The results showed that both tea polyphenols and tea pigments effectively reduced the GST-Pi expression at both transcription and translation level. It is concluded that the inhibition of tea polyphenols and tea pigments on GST-Pi overexpression induced by chemical carinogen may be one of the mechanisms of their inhibition on the occurrence and progression of liver precancerous lesions in rats.

Animals↗

PubMedDate not supplied

[Effect of DNAase on fluorescent properties of pigment-protein complexes, contained in photosystem II].

It was found that chlorophyll fluorescence spectra and spectra of fluorescence excitation of pigment-protein complexes of photosystem II are affected by treatment with DNase. Pigment-protein complexes were isolated from pea thylakoid membranes. Spectra were measured at room temperature. It was shown that the treatment with DNase leads to a 30% increase in fluorescence yield at excitation in chlorophyll absorption bands in the fraction containing CP47, CP43, and CP29, and also in the fraction containing reaction center complexes with minor contaminations of light-harvesting complexes. Upon excitation at 260-300 nm and in the region of 500 nm, a diminishing of fluorescence yield takes place. These results suggest that pigments and/or pigment-protein complexes are bound to nucleic acids. This association, by influencing the pigment properties, can participate in the photoregulation of biochemical reactions through changes in the thermal dissipation of excited chlorophyll molecules.

Deoxyribonucleases↗

PubMedDate not supplied

[Photosynthetic pigments of tomato under conditions of biotic stress and effects of furostanol glycosides].

Adaptogenic effect of furostanol glycosides (FG) on biosynthesis of photosynthetic pigments in tomato plants (Lycopersicon esculentum Mill.) were studied under conditions of biotic stress caused by root-knot nematode (Meloidogyne incognita Kofoid et White). Treatment of plants with 5 x 10(-4) M FG was accompanied by an increase in the rate of biosynthesis of pigments (particularly, chlorophyll b and carotenoids), which was observed against the background of a decrease in the relative contribution of beta-carotene and an increase in the relative contribution of pigments of violaxanthin cycle (VXC) to the overall pool of carotenoids. It was suggested that FG stimulated phytoimmunity by shifting metabolism of carotenoids toward enhanced biosynthesis of VXC pigments. These pigments play a protective role and facilitate stabilization of photosynthetic apparatus, which is particularly important under stress conditions.

Animals↗

PubMedDate not supplied

[Model of aggregation of pigments in the chlorosomal antenna of the green bacteria Chloroflexus aurantiacus].

Independent experimental and theoretical evaluation was performed for the adequacy of our previously proposed general molecular model of structural organization of light-harvesting pigments in chlorosomal bacteriochlorophyll (BChl) c/d/e-containing superantenna of different green bacteria. Simultaneous measurement of hole burning in the optical spectra of chlorosomal BChl c and temperature dependence of steady-state fluorescence spectra of BChl c was accomplished in intact cells of photosynthetic green bacterium Chloroflexus aurantiacus; this allows unambiguous determination of the structure of exciton levels of BChl c oligomers in this natural antenna, which is a fundamental criterion for adequacy of any molecular model for in vivo aggregation of antenna pigments. Experimental data were shown to confirm our model of organization of oligometric pigments in chlorosomal BChl c antenna of green bacterium Chloroflexus aurantiacus. This model, which is based on experimental data and our theory of spectroscopy of oligomeric pigments, implies that the unit building block of BChl c antenna is a cylindrical assembly containing six excitonically coupled linear pigment chains whose exciton structure with intense upper levels provides for the optimal spectral properties of the light-harvesting antenna.

Chloroflexus↗

PubMed2004

Assessment of polymorphic variants in the melanocortin-1 receptor gene with cutaneous pigmentation using an evolutionary approach.

The melanocortin-1 receptor gene (MC1R) encodes a membrane-bound receptor protein that is central to melanin synthesis. The coding region of MC1R is highly polymorphic and associations of variants with pigmentation phenotypes and risk for cutaneous neoplasms have been reported. We sought to determine the distribution and frequency of MC1R variants and their relationship to pigmentation characteristics in 179 Caucasian controls from the United States. One hundred thirty-five (75.4%) subjects carried one or more variants, and we determined that carriage of the previously designated "red hair color" (RHC) alleles, R151C, R160W, and D294H was strongly associated with fair pigmentation phenotypes including light hair and eye color, tendency to burn, decreased tendency to tan, and freckling. We used SIFT software to define MC1R protein positions that were predicted intolerant to amino acid substitutions; detected variants that corresponded to intolerant substitutions were D84E, R142H, R151C, I155T, R160W, and D294H. Carriage of one or more of these putative functionally important variants or the frameshift variant ins86A was significantly associated with fair pigmentation phenotypes. Analyses limited to carriage of ins86A and the three non-RHC alleles identified by SIFT were attenuated and no longer reached statistical significance. This is the first study to describe MC1R variants among control subjects from the U.S. Our results indicate that the frequency of variants is similar to that previously observed among non-U.S. Caucasians. Risk variants defined by either the published literature or by evolutionary criteria are strongly and significantly associated with all fair pigmentation phenotypes that were measured.

Adult↗