Chemical peelings for the treatment of actinic keratosis: a systematic review and meta-analysis.

BACKGROUND: Actinic keratosis (AK) is a common precancerous lesion of the skin that may be treated with chemical peelings. Despite their long-standing usage and clinical experience, no evidence-based recommendation regarding the efficacy and safety of chemical peelings for AK exists. OBJECTIVES: To systematically review and synthesize the current knowledge on chemically exfoliative peelings as interventions for AK. METHODS: We performed a systematic literature research in Medline, Embase and CENTRAL and hand-searched pertinent trial registers for eligible records until 5 August 2019. Results from individual studies were pooled using a random-effects model or described in a qualitative synthesis. The risk of bias was estimated with the tools provided by the Cochrane Collaboration (randomized and non-randomized trials) and the Evidence Project (single-arm trials). RESULTS: Four randomized controlled trials, two non-randomized controlled trials and two single-arm studies with a total sample size of n = 170 patients were included. Trichloroacetic acid (TCA) plus Jessner's solution showed significantly lower participant complete clearance (RR 0.36, 95% CI: 0.14-0.90, two studies, I2  = 0%, P = 0.03) and lower lesion clearance (RR 0.92, 95% CI: 0.85-0.99, one study, P = 0.03) compared to 5-fluorouracil (5-FU) 5% cream. TCA as monotherapy showed lower lesion complete clearance (RR 0.75, 95% CI: 0.69-0.82, two studies, I2  = 7%, P < 0.001) and lower mean lesion reduction per patient compared to conventional photodynamic therapy (cPDT) (MD -20.48, 95% CI: -31.55 to -9.41, two studies, I2  = 43%, P = 0.0003). Pain was more pronounced in patients treated with cPDT in comparison with TCA (MD -1.71 95% CI: -3.02 to -0.41, two studies, I2  = 55%, P = 0.01). In the single-arm studies, 5-FU plus glycolic acid showed 92% lesion clearance and phenol peeling 90.6% participant complete clearance. All studies showed a high risk for bias. CONCLUSIONS: Future high-quality studies and a standardization of peeling protocols are warranted to determine the value of chemical peelings in the treatment of AK.

Determination of endocrine disruptors and endogenic androgens and estrogens in rat serum by high-performance liquid chromatography-tandem mass spectrometry.

To simultaneously measure some targeted endocrine disruptors and several forms of sex hormones in rat serum, an accurate analytical procedure was developed. First, a comparison between a polymeric-based solid-phase extraction (SPE) and a micro-extraction by packed sorbent was performed to choose the optimal method to extract and concentrate the analytes: bisphenol A, atrazine, vinclozolin metabolite, testosterone, androstenedione, estrone, estradiol, estrone-sulfate and glucuronide and estradiol-sulfate and glucuronide. The analyses were then performed by high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionisation in positive and negative modes. The protocol based on SPE was validated using the ICH/2005 guidelines. The validation demonstrated good performance in terms of linearity (R(2)>0.99), recovery (71-90%) and repeatability (relative standard deviation: 1-18%). The method was sensitive with LOQ comprised between 0.1 and 0.4 ng/ml for androgens and between 0.098 and 10.2 ng/ml for estrogens. The results obtained on the serum of rats exposed to the targeted endocrine disruptors showed the suitability of this analytical strategy.

[Chemical peel treatments in dermatology]. / Chemische Peels in der Dermatologie.

Chemical peel treatments, which utilize a number of chemical peeling solutions subject to patient indication, are an easy to learn therapeutic technique suited for, in particular, various types of acne, acne scars, actinic keratosis and "sun-damaged skin". Especially the positive and long-lasting results of deep peels in the area of skin rejuvenation are deemed the gold standard against which other techniques, including lasers, must compare themselves. Other benefits of chemical peels include the flexibility to mix and match chemical solutions to custom design the treatment best suited for the desired degree of skin penetration, as well as the relatively low cost.

Micropollutants in urban stormwater: occurrence, concentrations, and atmospheric contributions for a wide range of contaminants in three French catchments.

This study aimed at: (a) providing information on the occurrence and concentration ranges in urban stormwater for a wide array of pollutants (n = 77); (b) assessing whether despite the differences between various catchments (land use, climatic conditions, etc.), the trends in terms of contamination level are similar; and (c) analyzing the contribution of total atmospheric fallout (TAF) with respect to sources endogenous to this contamination. The studied contaminants include conventional stormwater contaminants (polycyclic aromatic hydrocarbons (PAHs), Zn, Cu, Pb, etc.), in addition to poorly or undocumented pollutants such as nonylphenol and octylphenol ethoxylates (NPnEO and OPnEO), bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), a wide variety of pesticides, and various metals of relevance (As, Ti, Sr, V). Sampling and analysis were performed using homogeneous methods on three urban catchments with different land use patterns located in three distinct French towns. For many of these pollutants, the results do not allow highlighting a significant difference in stormwater quality at the scale of the three urban catchments considered. Significant differences were, however, observed for several metals (As, Cr, Cu, Ni, Sr and Zn), PAHs, and PBDEs, though this assessment would need to be confirmed by further experiments. The pollutant distributions between dissolved and particulate phases were found to be similar across the three experimental sites, thus suggesting no site dependence. Lastly, the contributions of TAF to stormwater contamination for micropollutants were quite low. This finding held true not only for PAHs, as previously demonstrated in the literature, but also for a broader range of molecules such as BPA, NPnEO, OPnEO, and PBDEs, whose high local production is correlated with the leaching of urban surfaces, buildings, and vehicles.

Adverse reactions caused by consecutive injections of different fillers in the same facial region: risk assessment based on the results from the Injectable Filler Safety study.

BACKGROUND: The combination of different injectable fillers in one area is considered to increase the risk of adverse reactions. OBJECTIVES: To characterize adverse reactions in patients who received more than one filler in the same facial region. METHODS: Data (up to July 2009) of the Injectable Filler Safety Study, a German-based registry for adverse filler reactions, was analysed descriptively. All cases were discussed individually. RESULTS: In 22 of the 161 patients (13.7%), two or more different fillers were injected consecutively into the same facial region. All patients were female with an average age of 50.6 (SD 13.6) years. In 12 of the 22 patients (54.5%), a specific filler could be attributed to the adverse reactions whereas in the other 10 patients (45.5%), the filler was not clearly attributable to one filler substance causing the adverse reactions. CONCLUSIONS: With the continuous changes in the filler market, the combination of different fillers in one area becomes more likely. Based on our data, there is not a lot of evidence that the combination of different injectable fillers, specifically biodegradable fillers, in the same region increases the risk of adverse reactions.

[History and use of fillers for treating wrinkles]. / Historie und Anwendung der Filler zur Faltenbehandlung.

The development of injectable fillers for filling in depressions or wrinkles in the face is reviewed. After the hesitant interest on fillers to correct scars and depressions which started at the end of the 19th century, the development of new substances continued at a dizzying pace when public demand to treat the signs of aging increased dramatically starting in the mid 1980s. This led to a countless number of different substances. To obtain an optimal result in treating facial wrinkles or depressions the appropriate filler must be injected with a technique that suits best the individual indication. Fillers are classified in resorbable and non-resorbable permanent fillers. With resorbable fillers only a temporary result can be obtained, which means that the patient has to undergo repetitive treatments. With permanent, non-resorbable fillers long lasting results can be obtained that may last for years and even decades. All fillers may have side effects like swelling, erythema, nodules right after treatment and in very rare cases years after the injection foreign body granulomas may develop that may be resistant to treatment.

[Chemical peels]. / Chemical Peel Anweisungen für die Praxis.

Chemical peels have become established over the past 40 years as an effective outpatient method for skin rejuvenation as well as the treatment of a variety of skin conditions. Although laser skin rejuvenation has claimed much attention in recent years, phenol peels, despite problems with scarring and hypopigmentation, remains the gold standard for skin resurfacing [11], against which other methods should be evaluated [21]. We present both a theoretical overview of chemical peels and practical step-for-step instructions.

[Chemical peels in aesthetic dermatology]. / Chemical Peels in der ästhetischen Dermatologie.

Chemical peels are classified as very superficial (exfoliation), superficial (epidermal), medium (papillary dermal) and deep (reticular dermal). A successful peel depends upon a number of variables, such as choice of the peeling agent, its concentration, and the pressure and frequency of the applications; all must be adjusted to the patient's skin condition. Through standardization of the peeling agents, the level of injury can be determined pre-operatively and complications minimized. Trichloroacetic acid (TCA) is the most popular peeling agent used in different concentrations. It has the broadest spectrum of indications due to its versatility in combination with other peeling agents. Indications for superficial peels include skin resurfacing, wrinkles, actinically damaged skin, actinic keratoses and benign pigmented lesions. Superficial peels have the advantage that they can be used on most regions of the body. The use of different chemical peels, their varying effects and their potential complications are reviewed. There are at present more than 45 chemical peels with different combinations of agents available on the European market.

Inhibition of spermidine synthase gene expression by transforming growth factor-beta 1 in hepatoma cells.

We screened genes responsive to transforming growth factor-beta (TGF-beta 1) protein in a human hepatoma cell line (Hep3B) using a PCR-mediated differential display technique, in order to investigate the mechanisms involved in TGF-beta-induced growth suppression. We found a gene that was down-regulated by TGF-beta 1 to be completely identical in an approx. 620 bp segment to the gene for the enzyme spermidine synthase, which mediates the conversion of putrescine into spermidine. Both spermidine synthase mRNA expression and its enzyme activity were decreased after TGF-beta 1 treatment of Hep3B cells. The inhibition of spermidine synthase gene expression by TGF-beta 1 protein was also observed in other hepatoma cell lines. The expression of genes for other biosynthetic enzymes in polyamine metabolism (ornithine decarboxylase and S-adenosylmethionine decarboxylase) was also inhibited to the same extent as for spermidine synthase, while the gene expression of spermidine/spermine N1-acetyltransferase, a catabolic enzyme, was relatively resistant to TGF-beta 1. Spermine levels in Hep3B cells were decreased by TGF-beta 1 treatment, although the levels of spermidine and putrescine were unchanged, probably due to compensation by remaining spermidine/spermine N1-acetyltransferase activity. Exogenously added spermidine or spermine, but not putrescine, partially antagonized the growth-inhibitor effects of TGF-beta 1 on Hep3B cells. Our data suggest that down-regulation of gene expression of the enzymes involved in polyamine metabolism, including spermidine synthase, may be associated with the mechanism of TGF-beta-induced growth suppression.

Synthesis and evaluation of a polyamine phosphinate and phosphonamidate as transition-state analogue inhibitors of spermidine/spermine-N1-acetyltransferase.

Polyamine analogues such as bis(ethyl)norspermine and N1-ethyl-N11-[(cyclopropyl)methyl]-4,8-diazaundecane (CPENSpm) act as inhibitors of the enzyme spermidine/spermine-N1-acetyltransferase (SSAT) in vitro and possess impressive antitumor activity against a number of cell lines. However, the propensity of these compounds to superinduce SSAT in intact cells limits their usefulness in studies aimed at elucidating the role of SSAT in cellular metabolism. The recently synthesized alkylpolyamine analogue N1-ethyl-N11-[(cycloheptyl)methyl]-4,8-diazaundecane (CHENSpm, 3) is also an effective inhibitor of SSAT and has potent antitumor activity, but does not appear to superinduce SSAT. These findings suggest that it is possible to synthesize polyamine analogues that can be used for selective inhibition of the enzyme in cellular metabolic studies. Along these lines, the phosphate-based transition state analogues 4 and 5 were synthesized and evaluated as inhibitors of isolated SSAT. Phosphonamidate 4 was rapidly hydrolyzed under the assay conditions, and thus did not inhibit the enzyme. However, the phosphinate analogue 5 was an effective inhibitor of purified human SSAT, with a Ki value of 250 microM. The inhibitory activity of 5 was also compared with that of CHENSpm (IC50 = 13 microM), as well as a series of bis-substituted alkylpolyamine analogues. The unsymmetrically substituted polyamine analogue CHENSpm (3) and the phosphinate transition state analogue 5 represent the first functional, nonsuperinducing inhibitors of human SSAT.

Effect of expression of human spermidine/spermine N1-acetyltransferase in Escherichia coli.

A plasmid expression vector, pINSAT2, was constructed in order to express spermidine/spermine N1-acetyltransferase (SSAT) in Escherichia coli. Cells transfected with this vector produced large amounts of SSAT, amounting to up to 2% of the soluble protein when isopropyl beta-D-thiogalactopyranoside (IPTG) was added and 0.3% of the soluble protein in the absence of inducer. The growth rate of cells expressing SSAT was reduced, and all of the cellular spermidine was converted to N1-acetylspermidine, much of which was excreted. Putrescine and 1-methylspermidine, which is not a substrate for SSAT, could reverse the effects of SSAT expression on growth, but spermidine was only effective when the amount of SSAT expression was limited by omitting the IPTG inducer. The lack of stimulation of growth by spermidine correlated with its complete conversion to N1-acetylspermidine. These results show that N1-acetylspermine is not able to substitute for the unmodified polyamines in supporting growth and suggest that acetylation is a physiological response to convert excess polyamines to a physiologically inert form which is readily excreted. Cells expressing large amounts of SSAT were much more sensitive to the growth inhibitory action of the antitumor agent N1,N12-bis(ethyl)spermine, supporting the hypothesis that the ability of such bis(ethyl) polyamines to induce SSAT contributes to their antiproliferative actions. SSAT was readily purified to homogeneity from extracts of DH5 alpha cells containing pINSAT2. The purified enzyme had a similar specific activity and Km values for spermine and spermidine as the enzyme purified from human colon cancer cells, suggesting that posttranslational modifications specific to eukaryotes are not needed for enzymatic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of chronic 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxy- adenosine (AbeAdo) treatment on polyamine and eIF-5A metabolism in AbeAdo-sensitive and -resistant L1210 murine leukaemia cells.

We have previously reported that prolonged chronic exposure to the S-adenosyl-L-methionine decarboxylase (AdoMetDC) inhibitor, 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxy-adenosine (MDL 73811, AbeAdo), leads to cytostasis of L1210 cells [Byers, Ganem and Pegg (1992) Biochem. J. 287, 717-724]. Further studies to investigate the mechanism by which these effects are brought about were carried out by comparing an L1210-derived cell line (R20) that is resistant to AbeAdo with the parent cells. The R20 cells were derived by two rounds of AbeAdo-induced cytostasis followed by rescue with exogenous polyamines. Cytostasis was induced in L1210 cells treated for 12 days with 10 microM AbeAdo; however, exposure to up to 40 microM AbeAdo did not induce cytostasis in R20 cells. Putrescine levels were elevated and spermine levels were depleted in both treated L1210 and treated R20 cells. Spermidine was depleted in treated L1210 cells but was only partly reduced in treated R20 cells. AdoMetDC activity was below the limit of detection in treated L1210 cells but, although greatly reduced, could be measured in the treated R20 cells. The resistance of the R20 cells to the effects of AbeAdo on cell growth and spermidine depletion correlated with reduced AbeAdo accumulation by R20 cells. In the absence of spermidine synthesis, unhypusinated eukaryotic translation initiation factor 5A (eIF-5A) accumulated in AbeAdo-treated L1210 cells. There was no detectable accumulation of unhypusinated eIF-5A in R20 cells. Unhypusinated eIF-5A accumulated during AbeAdo treatment was depleted in L1210 cells rescued by exogenous spermidine. These findings are consistent with the hypothesis that AbeAdo-induced cytostasis is due to the loss of hypusinated eIF-5A. However, spermine was able to rescue AbeAdo-treated L1210 cells without significantly reducing the unhypusinated eIF-5A accumulated during AbeAdo treatment, suggesting that only a small amount of the unmodified protein must be hypusinated to restore cell growth.

Nucleotide sequence of hamster spermidine/spermine-N1-acetyltransferase cDNA.

The nucleotide sequence of a cDNA encoding hamster spermidine/spermine-N1-acetyltransferase, a key enzyme in polyamine degradation and excretion, has been determined. The cDNA consists of a 1016 base pair insert including 120 nucleotides of the 5' untranslated region and the complete 3' untranslated region. The deduced amino acid sequence is very similar to the human spermidine/spermine-N1-acetyltransferase with only 8 differences in 171 amino acids and the corresponding nucleotide sequence shows 91% identity. The 5' untranslated regions are even more closely related with 97% identity suggesting that this region may play a role in the regulation of acetyltransferase activity. Translation of the acetyltransferase mRNA in a reticulocyte lysate was not altered by the addition of N1,N12-bis(ethyl)spermine.

Production of antibodies to peptide sequences present in human O6-alkylguanine-DNA alkyltransferase and their use to detect this protein in cell extracts.

Antisera were raised in rabbits to three peptides which correspond to sequences of amino acids present in human O6-alkylguanine-DNA alkyltransferase (residues 1-11, 8-20 and 197-207). These antisera recognized the alkyltransferase protein on Western blots of proteins from a number of Mer+ human tumor cell lines but this protein was found to be absent from Mer- tumor cell lines. The alkyltransferase protein was also detected by these antisera in some extracts from human liver samples but other human liver extracts having a high alkyltransferase activity failed to react with antibodies directed towards the carboxyl terminus of the protein, suggesting that part of this region can be removed by protease action without loss of activity or that there is genetic variability in this region. This result indicates that studies with a number of antisera or with an antibody known to be directed towards an essential, invariant region of the alkyltransferase will be needed for unequivocal detection of the alkyltransferase by antibody screening. The immunoreactive human alkyltransferase protein was absent from CHO cell lines that had previously been selected for alkyltransferase expression after transfection with human DNA. It is therefore probable that the hamster gene has been reactivated in these cells.

Use of antibodies to human O6-alkylguanine-DNA alkyltransferase to study the content of this protein in cells treated with O6-benzylguanine or N-methyl-N'-nitro-N-nitrosoguanidine.

Antisera raised in rabbits to three peptides corresponding to amino acid sequences found in human O6-alkylguanine-DNA alkyltransferase were used to study the fate of the alkyltransferase protein in human colon tumor cells after exposure to N-methyl-N'-nitro-N-nitrosoguanidine or to O6-benzylguanidine. Under these conditions, the alkyltransferase protein becomes inactivated, presumably by the conversion of its cysteine acceptor site to S-methylcysteine or S-benzylcysteine respectively. It was found that the protein was rapidly degraded after such inactivation both in intact cells and in cell-free extracts. It is probable that a conformational change in the protein is brought about by conversion of the alkyltransferase to the inactive form by alkylation of the cysteine acceptor site. This change may render the protein very sensitive to proteolytic degradation. The rapid degradation of the inactive form of the protein may serve as a signal for its resynthesis but in the short term ensures that its reactivation by regeneration of the cysteine acceptor site is unlikely to occur to any significant extent. The short half-life of the inactivated alkyltransferase protein makes it probable that measurement of the content of the alkyltransferase protein by immunohistochemistry, which is likely to measure the sum of the active and inactivated forms of the protein, will nevertheless yield an accurate estimation of the cellular capacity to repair O6-methylguanine provided that procedures with sufficient specificity and affinity can be developed.

Isolation and characterization of a cDNA clone that codes for human spermidine/spermine N1-acetyltransferase.

Spermidine/spermine N1-acetyltransferase (Spd/Spm acetyltransferase) is the rate-limiting enzyme in the catabolism of polyamines. This enzyme is highly inducible by several stimuli, including the natural polyamines and their structural analogues. To investigate the underlying mechanism responsible for the control of this enzyme a cDNA which codes for an active human Spd/Spm acetyltransferase has been isolated from a random primed cDNA library constructed from mRNA of a polyamine analogue treated large cell lung carcinoma line, NCI H157. The 972-base pair cDNA was identified using a 32-fold degenerate, 20-base oligomer probe to a 7-amino acid polypeptide sequence derived from the purified protein. The cDNA has a 513-base open reading frame that codes for a protein of 171 amino acids with a predicted molecular weight of 20,023. In vitro translation studies demonstrated the protein product of this cDNA to be a biologically active enzyme. The cDNA recognizes a 1.5-kilobase transcript in human cells which is highly induced in the human large cell lung carcinoma NCI H157 line following treatment with the polyamine analogue. The unusually high expression of Spd/Spm acetyltransferase mRNA by the NCI H157 cells in response to treatment does not appear to be a result of an amplification of the Spd/Spm acetyltransferase gene.

High specific induction of spermidine/spermine N1-acetyltransferase in a human large cell lung carcinoma.

The cytotoxic response of the human large cell lung carcinoma line NCI H157 to exposure to the polyamine analogue N1 N12-bis(ethyl)spermine (BESpm) is preceded by an extremely high induction of spermidine/spermine N1-acetyltransferase (SSAT). The human enzyme has now been purified greater than 300-fold to apparent homogeneity and found to cross-react with antisera raised against rat liver SSAT. Although other acetylases are capable of acetylating polyamines using acetyl-CoA as the acetyl donor, the greater than 600-fold induction within 24 h was found to be specifically SSAT, since essentially all activity was precipitable by the specific antisera. The human enzyme appears to be similar to the rat enzyme in subunit size under reducing conditions (approximately 20 kDa), substrate specificity and kinetic parameters. Preliminary results using actinomycin D and cycloheximide suggested that the unusually high induction by N1 N12-bis(ethyl)spermine in the human lung cancer line result from new mRNA and protein synthesis. This hypothesis is further substantiated here by 'in vitro' translation experiments comparing poly(A) mRNA from control and treated cells. The large cell lung carcinoma line NCI H157 represents a useful system to produce large amounts of the SSAT protein and to study the molecular events responsible for the induction and control of this important polyamine-metabolic enzyme. By using this rich source of SSAT protein, a partial amino acid sequence was determined by N-terminal sequencing of endoproteinase Lys-C digestion fragments. Further, this system should be useful in determining whether there is an association between the unusually high induction of the acetylase and the observed cytotoxicity in the NCI H157 cells.

Detection of proenzyme form of S-adenosylmethionine decarboxylase in extracts from rat prostate.

Previous work in which the synthesis of S-adenosylmethionine decarboxylase was studied by translation of its mRNA indicated that it was formed as a proenzyme having a M.W. of about 37,000 that was cleaved to form the enzyme sub-unit of M.W. 32,000 in a putrescine-stimulated reaction. The extent to which the proenzyme accumulates in vivo and is affected by the putrescine concentration was studied by subjecting prostate extracts to Western immunoblotting procedures. The proenzyme form was readily detectable in control prostates (about 4% of the total) and this proportion was increased to 25% when the rats were pretreated for 3 days with the ornithine decarboxylase inhibitor, alpha-difluoromethylornithine. Conversely, it was decreased to almost undetectable levels after treatment with methylglyoxal bis(guanylhydrazone). These results indicate that the processing of the proenzyme form of S-adenosylmethionine decarboxylase is regulated by the cellular putrescine concentration. This conversion provides another step at which polyamine biosynthesis may be controlled.