Vitiligo,Psoralen, and Melanogenesis: Some Observations and Understanding

Since the etiology of vitiligo is still unknown, we searched for some abnormal biochemical parameters, if any, in subjects with vitiligo. Higher urinary excretion of indole metabolites in vitiliginous patients have been noted, in association with higher dioxygenase, superoxide dismutase, and tyrosine aminotransferase activity in their serum. Similar results have also been found in an animal model, Bufo melanostictus, during induced tyrosinase inhibition. Treatment with psoralen can reverse the parameters, except tyrosine aminotransferase, to a normal level. Although psoralens are not the magic bullet for the therapy of vitiligo, they are still being used as a chemotherapeutic agent against vitiligo on a major scale to date. Tryptophan was found to participate in the pathway of melanogenesis, as a precursor as well as a positive regulator of tyrosinase. Its behavior in this regard is much more similar to the conventional substrates tyrosine and dopa (dihydroxyphenylalanine). In consideration of combined participation of tyrosine and tryptophan in the synthesis of melanin and its breakdown, the possible influence of different enzymatic reactions, like mono-oxygenase, dioxygenase, and deamination, has been suggested.     

Characterization of Vitiligo Antigens

Patients with vitiligo have circulating antibodies directed in part to pigment cell antigens with MWs of approximately 90, 75, and 40-45 kDs. These antigens are denominated VIT 90, VIT 75, and VIT 40, respectively. To further characterize these “vitiligo” antigens, we examined their relation to antigens defined by a panel of 25 monoclonal antibodies (moab) to pigment cell antigens. We found by immunoprecipitation and SDS-PAGE analysis of ¹²⁵I labelled, detergent soluble, human melanocyte macromolecules, that 24 (83%) of 29 patients with vitiligo had antibodies to one or more vitiligo antigens vs. 2 (7%) of 28 control individuals. Seventeen of the 25 moabs did not react with any labelled antigen in the same lysate. Of the remaining eight moabs, only four precipitated an antigen that co-migrated with one of the vitiligo antigens. Moab TA99, HMSA-5, and TMH-1 (all directed to the 75 kD tyrosinase-related protein [TRP1]) co-migrated with VIT 75. Moab W6/32 (directed to class I HLA antigen) co-migrated with VIT 40. Immunodepletion studies with vitiligo antibodies selectively depleted the antigen defined by W6/32 but not the antigen defined by TA99 and HMSA-5, indicating that VIT 75 was not the 75 kD tyrosinase-related protein. The vitiligo antigens were easily labelled by the lactoperoxidase technique but poorly labelled with ³⁵S-methionine, suggesting they are expressed on the cell surface. These studies indicate that VIT 90 and VIT 75 differ from antigens defined by currently available moabs to pigment cell antigens. VIT 40 appears to share a cross-reactive epitope, or be tightly bound to, class I HLA antigen.     

白癜风患者求医行为的调查研究

目的:本文的目的是研究白癜风患者的求医行为及男女性别之间的差异,分析患者选择医疗机构的原因并指导他们正确就医.方法:我们对210例白癜风患者进行问卷调查分析.访谈问卷内容包括人口统计学特征、白癜风知识、求医行为及原因、疾病的发展及心理状态的调查等.结果:仅14.3％的患者对自身疾病的基本知识回答正确,并且患者主要通过医生获得疾病知识;81.0％的患者首诊时选择公立综合医院,医疗技术水平(占69.9％)是患者在首诊时选择医疗机构的主要考虑方面,50.5％的患者存在多处求医的现象;81 4％的患者存在不同程度的心理压力.结论:白癜风患者普遍存在多处求医及不良求医行为,公立医院是目前白癜风患者的主要流向;白癜风患者的认知程度、心理状态等不容乐观;我们应针对白癜风患者多次求医和乱求医的行为及其原因开展白癜风健康教育,正规医疗机构应通过改善服务质量、提高疗效、加强宣传等促进白癜风患者正确求医.     

Metabolism of Catecholamines in the Developing Spinal Cord of the Rat

The metabolism of 3,4-dihydroxyphenylethylamine (DA, dopamine) and norepinephrine (NE) both normally, and after the administration of levo-3,4-dihydroxyphenylalanine (L-DOPA), has been studied in several regions of the developing spinal cord of the rat from fetal day (FD) 16 to the young adult stage. During late fetal (from FD 16) and most of neonatal life [to neonatal day (ND) 20], dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were either just detectable or present in very low concentration in all regions in the untreated developing rat. However, the developing spinal cord possesses an enormous capacity to metabolize the large amounts of DA synthesized from injected L-DOPA. At the end of 1 h after 100 mg/kg i.p. of L-DOPA, DOPAC and HVA are 54 +/- 14 (n = 5) and 16 +/- 5 (n = 5) nmol/g, respectively, in the thoracic zona intermedia in the 12-h-old (ND 0.5) rat. This metabolic capability is already highly developed as early as FD 16, peaks during the first half of neonatal life (ND 4 for DOPAC, and ND 15 for HVA), and is considerably reduced toward the end of neonatal life (approximately ND 28) and in the young adult. Control experiments suggest that a substantial part of this synthesis (from L-DOPA) and metabolism of DA occurs in elements other than the descending monoaminergic nerve fibers. By comparison, the synthesis and metabolism of NE develop more slowly, peak in the latter half of neonatal life, and then decline to the level found in the young adult.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transsynaptic Regulation of Olfactory Bulb Catecholamines in Mice and Rats

Norepinephrine (NE), dopamine (DA), 3,4-dihydroxyphenylalanine (DOPA), and 3,4-dihydroxyphenylacetic acid (DOPAC) were measured simultaneously by high performance liquid chromatography with electrochemical detection in extracts of olfactory bulbs at various intervals after chemical or surgical deafferentation. Chemical deafferentation of mice by intranasal irrigation with Triton X-100 or of rats by olfactory axotomy resulted in a rapid progressive decline of DA and DOPAC and an associated rise in NE in the olfactory bulb. However, after several weeks, these values returned to prelesion levels concomitant with reinnervation of the bulb by the afferent neurons. In contrast, deafferentation by procedures known to prevent reinnervation of the bulb by the afferent chemoreceptor neurons (i.e., a ZnSo4 solution in mice or a surgical procedure in rats) completely blocked the return to pre-lesion values of DA, DOPAC, and NE. The specificity of these effects was demonstrated by the inability of intranasal administration of the neurotoxin 6-hydroxydopamine to alter DA levels, resulting instead in a significant decline in olfactory bulb NE content. These data demonstrate that the DA content of the olfactory bulb can be influenced by either chemical or surgical modulation of the afferent pathway in two different species. This offers additional support for our hypothesis of transsynaptic regulation of intrinsic DA neurons of the bulb by the afferent olfactory chemoreceptor neurons.     

白癜风患儿抗核抗体、免疫球蛋白及补体检测的临床分析

目的:探讨白癜风患儿中抗核抗体(ANA)、免疫球蛋白(IgG、IgA、IgM)以及补体(C3、C4)的表达及临床意义。方法:收集2014年10月至2016年5月我院收治的30例白癜风患儿为病例组,并于同期随机选取30例健康体检儿童为对照组,患儿的血清ANA、12种自身抗体谱分别采用间接免疫荧光法及免疫印迹法进行检测,IgG、IgA、IgM,C3、C4水平采用免疫透射比浊法进行检测。结果:病例组中ANA阳性率为13.33%(4/30),与对照组的3.33%(1/30)比较,差异无统计学意义(P0.05)。12种自身抗体谱中,分别有1例(3.33%)患儿dsDNA、SmDNA、SS-A/Ro60KD、SS-B/La、CENP-B阳性,与对照组比较,差异均无统计学意义(P0.05)。病例组患儿血清IgG、IgA、C4水平低于对照组,差异有统计学意义(P0.05)。ANA阳性患儿血清IgG、IgA、IgM水平高于ANA阴性患儿,而补体C3、C4水平低于ANA阴性患儿,差异有统计学意义(P0.05)。结论:白癜风患儿ANA阳性表达与健康儿童无明显区别,体液免疫功能有明显异常,临床有重要的参考价值。     

Antioxidant Status in the Blood of Patients With Active Vitiligo

We have previously reported that patients with active vitiligo (AVP) have elevated urinary levels of catecholamine metabolites, such as homovanillic and vanilmandelic acids, irrespective of the form of the disease (acrofacial, segmental, generalized). We have suggested that abnormal release of catecholamines from autonomic nerve endings might play an etiological role in the onset and development of vitiligo through an overproduction of toxic (oxy)radicals in the microenvironment of melanocytes in the affected areas. In the present study we have investigated whether this suggested increase in radicals might be associated with an oxidative stress in the blood of AVP. We have analyzed by gas-chromatography mass-spectrometry, by high pressure liquid chromatography, by spectophotometry plasma levels of vitamin E (Vit E), lipoperoxides (LIP), and polyunsaturated fatty acids of phospholipids (PL-FA), erythrocyte reduced glutathione (GSH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in 62 patients affected with different forms of active vitiligo (acrofacial, segmental, generalized) and in 60 age-matched controls. Our results show that blood levels of Vit E, SOD, GSH, GSH-Px activity, LIP and PL-FA in AVP were not significantly different from those of healthy age matched controls, indicating that melanocyte damage in vitiligo is not linked with a generalized oxidative stress.     

Catecholamines in fetal pig plasma and the response to acute hypoxia and chronic fetal decapitation

Summary Dopamine, norepinephrine and epinephrine were measured by radioenzymatic assay in blood plasma samples drawn from the umbilical arteries of 30 anaesthetised Landrace pig fetuses. Just prior to term, the concentrations of dopamine (0.46±0.14 ng·ml^–1) and norepinephrine (1.74±0.60 ng·mg^–1) were lower than earlier in gestation, whereas epinephrine concentrations at term (0.80±0.31 ng·ml^–1) were similar to those at mid-gestation, intervening stages of gestation having higher levels of plasma epinephrine. Fetal hypoxia was induced by clamping the umbilical cord for 2 min and the catecholamines determined in arterial blood samples immediately thereafter, then again 3 min after removal of the clamp. Inconsistent effects of cord clamping on catecholamine levels were seen at 55 days, but thereafter, in all but one instance, the hormone levels were increased. Fetuses near term tended to respond less than fetuses at 75 and 96 days gestation (term=114±1 day). Catecholamines were also present in the circulation of fetuses decapitated at 42 days gestation and studied at 109±1 days. The average concentrations of dopamine (1.12±0.27 ng·ml^–1) and norepinephrine (8.23±3.04 ng·ml^–1) were greater than in intact fetuses, the plasma epinephrine levels being comparable to, or slightly higher than, those in intact fetuses. The results demonstrate that catecholamines are present in the circulation of the intact and decapitated pig fetus and that the actual concentrations and the type of response to umbilical cord clamping are dependent on gestation age.     

Catecholamines in Drosophila melanogaster (wild type and ebony mutant) decuticalarized retinas and brains.

The concentrations of catecholamines were determined in the decuticalarized retinas and brains at different ages in wildtype and ebony Drosophila melanogaster using the HPLC-technique with an electrochemical detector. L-Dopa, dopamine (DA), α-methyldopa (α-MD) and unidentified compounds X₁, X₂ and X₃ were found in decuticalarized retinas and brains of wildtype and ebony at different ages. Retinas and brains of the mutant ebony have higher concentrations of L-Dopa, DA and α-MD than the wildtype. In both wildtype and ebony, the concentrations of X₁, X₂ and X₃ were found to be higher in decuticalarized retinas than in brains. The identity and importance of X₁, X₂ and X₃ are still unknown.     

Catecholamines and catecholamine-synthesizing enzymes in guinea-pig sensory ganglia

Summary Cranial and spinal sensory ganglia of the guinea-pig were investigated by means of histochemistry and biochemistry for the presence of catecholamines and catecholamine-synthesizing enzymes. Sensory neurons exhibiting immunoreactivity to the rate-limiting enzyme of catecholamine synthesis, tyrosine nydroxylase (TH), were detected by immunohistochemistry in lumbo-sacral dorsal root ganglia, the nodose ganglion and the petrosal/jugular ganglion complex. The carotid body was identified as a target of TH-like-immunoreactive (TH-LI) neurons by the use of combined retrograde tracing and immunohistochemistry. Double-labelling immunofluorescence revealed that most TH-LI neurons also contained somatostatin-LI, but TH-LI did not coexist with either calcitonin gene-related peptide- or substance P-LI. TH-LI neurons did not react with antibodies to other enzymes involved in catecholamine synthesis, i.e., aromatic amino acid decarboxylase (AADC), dopamine--hydroxylase (DH), and phenylethanolamine-N-methyltransferase (PNMT). Petrosal neurons as well as their endings in the carotid body lacked dopamine- and L-DOPA-LI. Sensory neurons did not display glyoxylic acid-induced catecholamine fluorescence. Ganglia containing TH-LI neurons were kept in short-term organ culture after crushing their roots and the exiting nerve in order to enrich intra-axonal transmitter content at the ganglionic side of the crush. However, even under these conditions, catecholamine fluorescence was not detected in axons projecting peripherally or centrally from the ganglia. Sympathetic noradrenergic nerves entered the ganglia and terminated within them. Accordingly, biochemical analyses of guinea-pig sensory ganglia revealed noradrenaline but no dopamine. In conclusion, catecholamines within guinea-pig sensory ganglia are confined to sympathetic nerves, which fulfill presently unknown functions. The TH-LI neurons themselves, however, lack any additional sign of catecholamine synthesis, and the presence of enzymatically active TH within these neurons is questionable.     

Effects of Aging on p- and m-Octopamine, Catecholamines, and Their Metabolizing Enzymes in the Rat

Abstract: Functions of octopamine in the mammalian brain are still not well known. An important aspect of this problem is the relationship between octopamines and catecholamines. Previous data have shown that their respective ontogenic evolutions are not parallel. Do the changes in brain related to aging also differentially affect these two groups of molecules? In order to check this point, the brain levels of p- and m-octopamine, p-tyramine, noradrenaline, and dopamine, as well as the activities of metabolizing enzymes, were determined in young adult and aging rats (20–26 months). Unlike catecholamines, there is a drastic decrease of p-octopa-mine after 20 months of age in the hypothalamus and telencephalon. p-Tyramine levels are also lowered. This change appears to be due to a decrease of the aromatic L-amino acid decarboxylase activity. These data, as those of ontogenic studies, confirm that p-octopamine and catecholamine metabolisms may have some independent steps and, moreover, that p-octopamine may have a role in the normal activity of the brain.     

Catecholamines induce metamorphosis in the hydrozoan Halocordyle disticha but not in Hydractinia echinata

Summary Planula larvae of the marine hydroids Halocordyle disticha and Hydractinia echinata were treated with the catecholamines epinephrine, norepinephrine and dopamine, as well as with certain of their precursors and agonists. Norepinephrine, l-dopa, dopamine and the dopamine agonist ADTN at concentrations ranging from 0.1 to 0.001 mM induced metamorphosis within 24 h in Halocordyle disticha, with no observable morphogenetic abnormalities. Epinephrine, the adrenergic agonists phenylephrine, isoproterenol and methoxyamine, and the catecholamine precursors phenylalanine and tyrosine were found not to induce metamorphosis at the concentrations employed. None of the compounds was effective in inducing metamorphosis in Hydractinia echinata. A model is presented for neural control of metamorphosis in Halocordyle disticha     

Secretion of Catecholamines from Individual Adrenal Medullary Chromaffin Cells

Abstract: Catecholamine secretion has been measured with electrochemical techniques from isolated, single adrenal medullary chromaffin cells with carbon-fiber microelectrodes. The electrode tip, which is of similar dimensions to the cell, is placed adjacent to the cell to enable the measurement of local secretion. Secretion is caused by exposing the cell to nanoliter volumes of solution containing nicotinic receptor agonists or depolarizing agents. The identification of secreted substances is made with cyclic voltammetry at both bare electrodes and electrodes coated with a perfluorinated cationexchange polymer. Catecholamine secretion is induced by nicotine (10–500 μ M ), carbamylcholine (1 m M ), and K⁺ (60 m M ). All agents that induce secretion lead to a broad envelope of secreted catecholamines on which sharp concentration spikes are superimposed. The concentration spikes can be monitored with a time resolution of tens of milliseconds when the electrodes are used in the amperometric mode. Release induced by nicotine and K⁺ is inhibited by Cd²⁺ (0.5 m M ), and hexamethonium selectively blocks the nicotineinduced secretion. The actions of nicotine are found to continue for a longer period of time than those of the other secretagogues tested.     

Relationship Between Phenolamines and Catecholamines During Rat Brain Embryonic Development In Vivo and In Vitro

p-Octopamine and phenylethanolamine are present in the embryonic rat brain earlier than catecholamines. These phenolamines are localized mainly in the hypothalamus, where the level of p-octopamine is very high. The parallel developmental study of the activities of dopamine beta-hydroxylase, 3,4-dihydroxyphenylalanine decarboxylase, tyrosine hydroxylase, and monoamine oxidase shows that phenolamines are present in significant amounts in the hypothalamus until tyrosine hydroxylase and monoamine oxidase become catalytically active. The culture of embryonic hypothalamus at different ages shows that no tyrosine hydroxylase and monoamine oxidase activities can be detected if the tissue is cultured before 15 days. This clearly indicates that all the enzymes related to catecholamine biosynthesis are not triggered at the same time during the development of the rat brain. These results are discussed on the basis of the physiological importance of phenolamines in mammals and of the use of the developing rat brain as a model for the study of the onset of the catecholaminergic system and the decline of the octopamine.     

Combined Stereological and Biochemical Analysis of Storage and Release of Catecholamines in the Adrenal Medulla of the Rat

Adrenal medullae from rats injected with insulin 1 h prior to decapitation were analyzed by stereology and their catecholamine content was determined. In control animals the ratio between adrenaline- and noradrenaline- containing cells was 4.06 whereas the ratio between adrenaline and noradrenaline contents was 4.11. The glands from insulin-treated animals showed a 45% reduction in adrenaline content and a 42% decrease in the volumetric density of the adrenaline-containing granules. However, neither the noradrenaline content nor the volumetric density of noradrenaline-containing granules was modified in glands from insulin-treated animals. From these data, the amount and concentration of adrenaline or noradrenaline in a single granule have been calculated. The results are consistent with the view that chromaffin granules are the source of the released catecholamines. The present paper demonstrates that stereology combined with biochemistry is a useful tool for resolution of problems at the cellular and subcellular levels.     

Catecholamines and dihydroxyphenylalanine in metamorphosing larvae of the nudibranch Phestilla sibogae Bergh (Gastropoda: Opisthobranchia)

The content of catecholamines and dihydroxyphenylalanine in larvae of the nudibranch Phestilla sibogae was analyzed by high-performance liquid chromatography with electrochemical detection. Dihydroxyphenylalanine, norepinephrine and dopamine were identified in larvae of all ages examined (5 through 12 days post-fertilization). Dihydroxyphenylalanine could be accurately quantified only in larvae of ages 8 through 12 days, when its average concentration increased from 0.62 to 6.71 × 10⁻² pmol μg protein⁻¹. Between ages 5 and 12 days dopamine rose from 0.081 to 0.616 pmol μg protein⁻¹, and norepinephrine from 0.45 to 2.17 × 10⁻² pmol μg protein⁻¹. Dihydroxyphenylalanine, dopamine and norepinephrine were also measured at different stages of metamorphic progress in 10- to 12-day larvae. Dihydroxyphenylalanine increased by a factor of 2.4 between the onset and completion of metamorphosis, but levels of dopamine and norepinephrine remained stable. One millimolar alpha-methyl-dl-m-tyrosine, an inhibitor of catecholamine synthesis, inhibited natural metamorphosis and depleted endogenous norepinephrine and especially dopamine, respectively, to 75% and 35% of control values. The existence of unexpectedly high levels of catecholamines in metamorphically competent larvae, and the association of catecholamine depletion with inhibition of metamorphosis, indicate that these compounds may participate in the control of gastropod development. Accepted: 18 April 1997     

Further Evidence for Involvement of Both Cell Mediated and Humoral Immunity in Generalized Vitiligo

Immunohistochemical and immunoserological evidence supports the involvement of both cell-mediated and humoral mechanisms in the pathogenesis of melanocyte destruction in vitiligo. Punch biopsies from depigmented vitiliginous skin (VS), normal-looking pigmented skin (PS), and marginal skin (MS) from patients with generalized vitiligo (n = 15) were labeled with K 1.2.58, OKM1 (CD11b), Leu 11b (CD16), Leu 19 (CD56), IFN-γreceptor, IL-2 receptor (CD25), IgG, IgM, C3c, and C3d MoAbs. In addition, in vitro effects of vitiligo sera (n = 13) on human newborn melanocytes (HMel) under different culture conditions were studied. The immunohistochemical findings showed absence of K 1.2.58+ epidermal melanocytes in VS and abnormal morphology in MS. In these areas, a few CD11b + cells in the dermis and epidermis could be detected but no significant numbers of CD16+ or CD56+ cells were seen among the mononuclear cellular infiltrate. IL-2 and IFN-γ receptors were clearly expressed by the cellular infiltrate. No significant deposition of complement or immunoglobulin was seen. The addition of vitiligo sera to HMel cultures induced a significant cellular proliferation. The stimulation of cell proliferation occurred regardless whether the sera were added alone or when preheated (56°C for 1 hr) and then supplemented with a complement source (P < 0.01 at 2%, P < 0.001 at 10%, and P < 0.01 at 20% for sera alone) (P > 0.05 at 2%, P < 0.05 at 10%, and P < 0.01 at 20% for decomplemented sera plus complement). In contrast, incubation of vitiligo sera together with normal lymphocytes with HMel significantly decreased the number of living melanocytes in a dose dependent manner, suggesting an antibody-dependent cellular cytotoxicity (ADCC) reaction (P < 0.01 at 2% and 10%, P < 0.001 at 20%). The presence of lymphocytic infiltrate at marginal skin with evidence for IL-2- and IFN-γ-receptor expression and the decrease in the number of living cells by ADCC-like mechanisms provide further support for an autoimmune pathogenesis in vitiligo.     

Regulation of Nervous System-Specific S-100 Protein and Enolase Levels in Adipose Tissue by Catecholamines

The effect of catecholamines on the levels of S-100 protein and nervous system-specific enolase (NSE) in epididymal adipose tissue of Wistar rats in vivo was examined by sensitive enzyme immunoassay methods. Soluble S-100 protein levels in the adipose tissue of 9-12-week-old rats (1.46 +/- 0.19 microgram/mg protein) were decreased to less than 50% of those of controls by serial injection (for 4-7 days) of epinephrine (0.1 mg/day) or norepinephrine (0.15 mg) with, however, little effect on the levels of membrane-bound (pentanol-extractable) S-100 protein. A significant decrease in the soluble S-100 protein levels was observed at 2 h after a single injection of epinephrine (1.04 +/- 0.13 microgram/mg protein). On the other hand, levels of NSE subunit (gamma subunit or 14-3-2 protein) in adipose tissue (0.51 +/- 0.03 gamma gamma-equivalent pmol/mg protein) were increased to 170% of control by serial injection (for 7 days) of epinephrine or norepinephrine with little change of the level of enolase alpha subunit on a mg protein basis. Isoproterenol had no apparent effect on the levels of soluble S-100 protein and NSE subunit. These results suggest that the levels of S-100 protein and NSE in adipose tissue are regulated by catecholamines.     

Catecholamines are involved in the mechanism of the urinary alcohol level cycle in rats fed ethanol intragastrically at a constant rate

Studies have indicated that blood alcohol levels cycle exists when ethanol is fed continuously using the intragastric feeding rat model of early alcoholic liver disease. The aim of the present study was to determine the role played by catecholamines in the pathogenesis of the blood alcohol cycling observed when ethanol is fed at a constant rate. The rats were tested at the peaks and troughs of the urinary alcohol level (UAL) cycle and the results were compared with controls. Blood catecholamine levels were markedly increased at the peaks, but not at the troughs. Propranolol, a beta adrenergic blocker, attenuated the amplitude of the cycle. Phenoxybenzamine, an alpha blocker disrupted the cycle and elevated ethanol to fatal levels. The results indicate that both alpha and beta adrenergic mechanisms are required for the cycle to occur.