Treatment of superficial vascular lesions with the KTP 532-nm laser: experience with 647 patients.

Superficial vascular lesions are a common dermatological diagnosis but are often difficult to treat. Numerous lasers (especially the dye laser) and intense pulsed light sources have been used, but there have been very few reports on the effectiveness of the potassium-titanyl phosphate (KTP) laser. We have extensive experience of this modality at our institution, and the purpose of this survey is to report on the safety and efficacy of the KTP laser. Using an in-house database, we retrospectively collected data from patients who had undergone treatment with the KTP laser for superficial vascular lesions. Patients of Fitzpatrick skin type I-IV were included. Exclusion criteria were Fitzpatrick skin type V, patients with obvious suntan and those on potentially phototoxic medications or minocycline therapy. Diagnoses included discrete or matted telangiectasia, strawberry naevus, spider angioma, rosaceal erythema, rosaceal telangiectasia, telangiectatic naevus, angioma, combined rosaceal erythema/telangiectasia, port-wine stain, venous lake haemangioma and hereditary haemorrhagic telangiectasia. Patients underwent an initial test treatment and further treatment at 6-week intervals as required. Clinical photographs were taken pre- and post-treatment, and outcome was graded by patient and physician. Adverse effects were recorded including scarring, hypo- or hyperpigmentation, marked swelling, blistering, scabbing and bruising. Six hundred forty-seven patients with 13 diagnoses on 9 different body sites were recorded. Four hundred eighty-six were female, and the median age was 39.5 years. Of the lesions treated, 33.7 % (n = 218) were discrete telangiectases and 31.8 % (n = 206) were spider angiomas. A 92.7 % of lesions were on the face. Four hundred thirteen (77.6 %) patients who had outcomes recorded at 6 weeks were graded as "clearance" or "marked improvement". Only 38 (5.8 %) patients experienced adverse effects, all of which were minor; the main adverse effect was swelling. Unlike the dye laser, there was only one case of bruising out of 647 patients. This is the largest survey of patients to have undergone KTP laser treatment reported in the literature. Our results show that the KTP laser is a safe and effective modality for the treatment of superficial vascular lesions.

Time course of exhaled hydrogen peroxide and nitric oxide during chemotherapy.

This study was designed to assess the effect of differential leukocyte depletion during chemotherapy by monitoring the levels of exhaled hydrogen peroxide H2O2 and nitric oxide (F(eNO)) present. In 39 patients with lung cancer (chronic obstructive pulmonary disorder up to stage II, median forced expiratory volume in one second 78% predicted), measurements were performed before a cycle of therapy (day 1), at least once during the cycle (day 8: n = 34; day 15: n = 19), and afterwards (days 21-29). There were significant changes in the level of H2O2, F(eNO) and peripheral blood cell differentials over the visits. The level of H2O2 was decreased only on day 15, with a median (difference between the upper and lower quartiles) fall of 31 (57)%, while F(eNO) was reduced only on day 8, by 22 (40)%. Neutrophil numbers were unchanged on day 8 and decreased by 59 (48)% on day 15, while monocyte numbers were decreased on day 8 by 87 (39)%. On days 21-29, values had returned to baseline. Taken together with previous findings, the parallel course of levels of exhaled hydrogen peroxide and neutrophil counts suggests that a major part of exhaled hydrogen peroxide is due to neutrophils via the conducting airways. In contrast, the production of exhaled nitric oxide seems to be primarily associated with monocytes.

Exhaled breath condensate: methodological recommendations and unresolved questions.

Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases. The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required. Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them. Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.

Determination and quantification of urinary metabolites after dietary exposure to acrylamide.

It is known that heat-treated carbohydrate-rich foods may contain high levels of acrylamide (AA) and up to 4000 microg kg-1 in potato crisps and 2000 microg kg-1 in French fries have been reported. In order to obtain more information on the human exposure to and metabolism of AA, a method for the determination of known urinary metabolites from the dietary exposure of AA using solid-phase extraction and liquid chromatography with positive electrospray MS/MS detection was developed. The validated assay range was from 8.6 to 342.9 microg l-1. The urinary metabolites were synthesized and their structures determined by NMR and MS. To test the method, a pilot study was conducted in which all urine during 48 h starting with 24 h fasting was collected. The two urinary metabolites, N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine (MA-GA3) and N-acetyl-S-(3-amino-3-oxopropyl)cysteine (MA-AA), were found to be above the detection limit. Fasting during 1 day caused about a 50% decrease in the total level of the metabolites, but after 1 day of a normal diet, the metabolite levels increased back to pre-fasting levels. The total amount of AA in the form of urinary metabolites excreted over the period was estimated to be about 40 microg AA day-1 for the average non-smoker.

Biomarkers of exposure to heterocyclic amines: approaches to improve the exposure assessment.

Various methods of exposure assessment, such as questionnaires, sometimes combined with pictures of cooked meat, have been employed in investigations on the relationship between heterocyclic amines (HA) and health effects. However, as the content of heterocyclic amines vary greatly with cooking conditions, it is difficult to obtain an accurate estimate of the exposure. To improve the exposure assessment, the use of biomarkers has been investigated. The metabolism of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is well characterised. In humans, the major part of the dose is excreted in urine within 24-48 h following a meal. A few percent is excreted as parent compounds, whereas the major part is metabolites. Urinary level of parent HA reflects only recent exposure. However, the pattern of excreted metabolites might indicate the capacity to activate or detoxify HAs. The excretion of glucuronide conjugates of N-hydroxy-PhIP and N-hydroxy-MeIQx could be a marker for the N-hydroxylation capacity and the dose of the proximate metabolites. Recently, we proposed 5-OH-PhIP as a marker for the ultimate reactive metabolite of PhIP, since it is formed from this compound as a by-product along with the formation of PhIP-DNA adducts. In a search for biomarkers reflecting exposure over some time, blood protein adducts with a longer lifespan have been investigated, and PhIP adducts of serum albumin and haemoglobin from meat-consuming humans were recently reported. Many compounds, like drugs, nicotine and narcotics, bind to melanin in hair and give information on exposure for longer time periods. In mice, PhIP is irreversibly incorporated in a dose-dependent manner into hair, and in humans exposed to an ordinary diet, it was found to vary from <50 to 5000 pg PhIP/g hair. The incorporation is also dependent on the content of eumelanin. The use of PhIP in hair as a biomarker of exposure is promising, but needs validation, using other methods of exposure assessment.

Pyrazolo[3,4-d]pyrimidine nucleic acids: adjustment of dA-dT to dG-dC base pair stability.

Oligonucleotides incorporating 8-aza-7-deazapurin-2,6-diamine (pyrazolo[3,4-d]pyrimidin-4,6-diamine) nucleoside 2a or its 7-bromo derivative 2b show enhanced duplex stability compared to those containing dA. While incorporation of 2a opposite dT increases the T(m) value only slightly, the 7-bromo compound 2b forms a very stable base pair which is as strong as the dG-dC pair. Compound 2b shows a similar base discrimination in duplex DNA as dA. The base-modified nucleosides 2a,b have a significantly more stable N-glycosylic bond than the rather labile purin-2,6-diamine 2'-deoxyribonucleoside 1. Base protection with acyl groups, with which we had difficulties in the case of purine nucleoside 1, was effective with pyrazolo[3,4-d]-pyrimidine nucleosides 2a,b. Oligonucleotides containing 2a,b were obtained by solid phase synthesis employing phosphoramidite chemistry. Compound 2b harmonizes the stability of DNA duplexes. Their stability is no longer dependent on the base pair composition while they still maintain their sequence specificity. Thus, they have the potential to reduce the number of mispairs when hybridized in solution or immobilized on arrays.

Determination of phenolic flame-retardants in human plasma using solid-phase extraction and gas chromatography-electron-capture mass spectrometry.

A method for determination of phenolic flame-retardants in human plasma utilizing solid-phase extraction (SPE) and gas chromatography with electron-capture mass spectrometric detection (GC-ECMS), has been developed. The plasma lipids were decomposed by application of concentrated sulphuric acid directly on the polystyrene-divinylbenzene SPE column. The method has been validated for 2,4,6-tribromophenol (TriBP), pentabromophenol (PeBP), tetrachlorobisphenol-A (TCBP-A) and tetrabromobisphenol-A (TBBP-A) in the concentration range 1.2-25, 0.4-40, 4-200 and 4-200 pg g(-1) plasma, respectively. The average absolute recovery of the analytes ranged from 51 to 85%. Tetrabromo-o-cresol and chlorotribromobisphenol-A were found suitable as internal standards, and the average recovery of the analytes relative to the internal standards was in the range 93-107%. The repeatability of the method was in the range 4-30% relative standard deviation. The estimated detection limits of TriBP, PeBP, TCBP-A and TBBP-A were 0.3, 0.4, 3.0 and 0.8 pg g(-1) plasma, respectively. The method has been used for analysis of plasma samples from potentially occupationally exposed human individuals.

Urinary excretion of leukotriene E4 and eosinophil protein X in children with atopic asthma.

Measurement of leukotriene E4 (LTE4) in urine is a noninvasive method for assessing changes in the rate of total body cysteinyl leukotriene production. Eosinophil protein X (EPX) has been used to assess eosinophil activity and monitor inflammation in bronchial asthma. The aim of the study was to look for differences in urinary LTE4 and EPX concentrations between children with stable atopic asthma and healthy controls and to compare asthmatic children with different disease severity. In addition the relationship was evaluated between urinary LTE4 and EPX levels and lung function. LTE4 was also measured (enzyme immunoassay) together with EPX (radioimmunoassay) in urine and lung function tests were carried out in children with mild asthma (steroid-naive) (n=49), moderate to severe asthma (using inhaled steroids) (n=31) and healthy control subjects (n=28). Urinary leukotriene E4 (LTE4) was significantly higher in children with asthma than in controls (median [25-75 percentile] 238.5 (126.5-375.7) SD 191.8 versus 189 (51-253.2) SD 131.7 pg.mg(-1) creatinine; p=0.021). Urinary EPX was also significantly increased in asthmatic children compared with controls (85.5 [64-131.5] SD 76.2 versus 48.5 [43.2-90] 112.1 microg x mmol(-1) creatinine; p=0.006). There were no differences in urinary LTE4 and EPX between the group of mild and the group of moderate to severe asthmatic children. There were significant associations between the urinary LTE4 and intrathoracic gas volume (ITGV), residual volume (RV), forced expiratory volume in one second (FEV1), forced expiratory capacity (FVC) and maximum expiratory flow rate at 25% of vital capacity (MEF25). Urinary EPX was only correlated with maximum expiratory flow rate at 75% of vital capacity (MEF75). Thus measurement of urinary LTE4 may predict the degree of airflow obstruction in asthmatic children. Urinary LTE4 and EPX are useful markers of airway inflammation and can be helpful in guiding asthma management. There was no correlation between LTE4 and EPX levels.

Water chlorination and birth defects.

Chlorination of drinking water that contains organic compounds leads to the formation of by-products, some of which have been shown to have mutagenic or carcinogenic effects. As yet, too little is known about the possible teratogenic effects on the human fetus. We linked the Norwegian waterwork registry, containing 1994 data on chlorination practice and color (an indicator for natural organic matter), with the Medical Birth Registry for 1993-1995. The proportion of the population exposed to chlorination and a weighted mean color number in drinking water was computed for each municipality. Among 141,077 births, 2,608 (1.8%) had birth defects. In a comparison between exposed (high color; chlorination) and reference groups (low color; no chlorination), the adjusted odds ratio was 1.14 (0.99-1.31) for any malformation, 1.26 (0.61-2.62) for neural tube defects, and 1.99 (1.10-3.57) for urinary tract defects. This study provides further evidence of the role of chlorination of humic water as a potential cause of birth defects, in a country with relatively low levels of chlorination byproducts.

[Chlorination of drinking water--possible cancer risk from a by-product]. / Klorering av drikkevann--mulig kreftrisiko av et biprodukt.

In a recent study, 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX; CAS no 77439-76-0) which is formed during chlorination of water containing organic substances, was found to be carcinogenic in the rat, at multiple sites in both sexes. MX is known as a potent bacterial mutagen. Epidemiological studies have suggested an association between chlorinated water consumption and a moderate increase in the risk of cancer. Although MX is a strong mutagen in prokaryotes, its genotoxic effects in mammalian cells are not so large, and more variable results are obtained. Very low concentrations of MX are found in drinking water (ng/L), whereas the genotoxic and carcinogenic effects in experimental animals of this compound are detectable at relatively high doses (mg/kg body weight). Relative to the risk for infectious diseases from the consumption of contaminated drinking water, the possible cancer risk associated with MX exposure appears to be low. Even so, efforts should be made to reduce disinfection byproduct formation by removing organic matter before chlorination.

Dioxins, PCBs and some chlorinated pesticides in human milk from the Kola Peninsula, Russia.

In 1993, 30 individual human milk samples were collected in Murmansk and Monchegorsk, and analysed for 23 polychlorinated biphenyl congeners, PCBs (IUPAC nos.) 28, 52, 66, 74, 99, 101, 105, 110, 114, 118, 128, 138, 141, 149, 153, 156, 157, 170, 180, 187, 194, 206, and 209. In addition, the following organochlorine pesticides (OCPs): hexachlorobenzene (HCB), the alpha-, beta-, gamma-isomers of hexachlorocyclohexane (HCH), the chlordanes: oxychlordane, trans-chlordane, cis-chlordane, trans-nonachlor, and cis-nonachlor, and the DDT-compounds: pp-DDE, pp-DDD, op-DDT and pp-DDT were detected. From each city, a pooled sample was made and analysed for non-ortho PCBs, dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). In addition one individual sample from Monchegorsk was analysed for PCDDs/PCDFs because of the very high levels of PCBs in this sample. High levels of pp-DDE and beta-HCH were found in Murmansk and Monchegorsk (in parenthesis) with mean levels of 1269, (892) and 853, (739) micrograms/kg milk fat respectively. Highest individual levels of pp-DDE (2816 micrograms/kg milk fat) and beta-HCH (1988 micrograms/kg milk fat) were found in Murmansk. Significant differences were found between the levels of gamma-HCH, cis-chlordane, trans-nonachlor, cis-nonachlor, pp-DDE, and the PCBs 28, 52, 74, 66, 110, 118, 105, 128, 206, and 209, between the two areas. No geographic differences in the concentrations of PCDDs/PCDFs and non-ortho PCBs in the sample pools from the two Russian areas were observed.

Congener-specific determination of polychlorinated biphenyls and organochlorine pesticides in human milk from Norwegian mothers living in Oslo.

Human milk samples from 28 mothers at Oslo City Hospital, Norway, were collected in 1991 and analyzed for individual polychlorinated biphenyl (PCB) congeners, IUPAC numbers 28, 74, 99, 101, 105, 114, 118, 128, 138, 141, 153, 156, 157, 170, 180, 194, and 206, plus selected non-ortho-substituted compounds, IUPAC numbers 77, 126, and 169. Sum DDTs (sum of concentrations of DDT and related compounds), hexachlorobenzene (HCB), oxychlordane, transnonachlor, and sum hexachlorocyclohexanes (HCHs) (sum of concentrations of alpha-HCH, beta-HCH, and gamma-HCH) were also determined. The mean levels of sum DDTs, HCB, oxychlordane, transnonachlor, and sum HCHs were 338, 41, 9, 19, and 36 ng/g, respectively, in human milk fat. p,p'-DDE and beta-HCH accounted for 81 and 93% of sum DDTs and sum HCHs, respectively. The mean level of sum PCBs (sum of mean concentrations of 20 individual congeners) was 372 ng/g milk fat. A very good correlation was found between sum PCBs and PCB-153 (r = .97). Sum PCBs determined on a capillary column was found to account for 62-79% of total PCBs calculated by using the packed column method used in previous human milk surveys in Norway. Comparison with previous results revealed that the mean sum PCB, HCB and sum DDT levels were decreased by 70, 65, and 75%, respectively during the past 9 yr. The contribution of individual PCDD/PCDF (earlier Norwegian study) and non- and mono-ortho-substituted PCB congeners to the total calculated toxic equivalent values was assessed, and the PCBs were found to constitute a major part of the TCDD equivalents in human milk, with PCB-126 as the main contributor.

Formation of a glutathione conjugate and a semistable transportable glucuronide conjugate of N2-oxidized species of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in rat liver.

We have previously shown that 2-hydroxamino-1-methyl-6-phenylimidazo[4,5-b]pyridine(2-h ydroxamino-PhIP) is the principal metabolite leading to mutations in Salmonella typhimurium TA98 and DNA damage in mammalian cells. In rat hepatocytes this metabolite can be further conjugated to 2-(N-beta-D-glucuronopyranosyl (hydroxamino)-1-methyl-6-phenylimidazo[4, 5-b]pyridine[N(OH)-gluc-PhIP]. Its rate of formation was increased in hepatocytes from polychlorinated biphenyl (PCB)-pretreated animals. This metabolite is the main metabolite of PhIP in bile and it is hydrolyzed both by human and rat intestinal bacteria. Smaller amounts are excreted into urine. The evidence for the proposed structure is based on 1H- and 13C-NMR, beta-glucuronidase-lability giving 2-hydroxamino-PhIP upon hydrolysis and on the results obtained by using biochemical enzyme inhibitors. N(OH)-gluc-PhIP may be important for genotoxic lesions and tumors of 2-amino-1methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) in extrahepatic tissue. In hepatocytes and bile from PCB-pretreated rats a PhIP-glutathione conjugate, 2-glutathionyl-1-methyl-6-phenylimidazo[4,5-b]pyridine (GSH-PhIP) was also found. The evidence for the proposed structure is based on 1H-NMR and high-resolution mass spectrometry. The metabolite can also be produced by a direct nucleophilic substitution of the nitro group in 2-nitro-PhIP by glutathione (GSH) in vitro. The metabolite did not form from 2-hydroxamino-PhIP and GSH either directly or in the presence of glutathione S-transferase. The formation of GSH-PhIP in rat liver and isolated cells only at a high rate of 2-hydroxamino-PhIP formation (PCB-treated animals) indicates that 2-nitro-PhIP may be formed in the liver during such N-oxidation of PhIP.

Genotoxic effects of the drinking water mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX) in mammalian cells in vitro and in rats in vivo.

The potent bacterial mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]- furanone) (MX), which is formed during chlorination of drinking water and accounts for about one third of the Ames mutagenicity of tap water, has been studied with respect to its genotoxicity in vitro and in vivo. Treatment with 30-300 microM MX (1 h) induced DNA damage in a concentration-dependent manner in suspensions of rat hepatocytes, as measured by an automated alkaline elution system. The effect was similar in hepatocytes from PCB-induced and uninduced rats. DNA damage was induced in V79 Chinese hamster cells and in isolated rat testicular cells, at the same concentration level as in hepatocytes. Pretreating testicular cells with diethylmaleate, which depletes 85% of cellular glutathione, had no significant effect on the DNA damage induced by MX. The treatment conditions used in the alkaline elution experiments were not cytotoxic to any of the cell types used, as determined by trypan blue exclusion. V79 cells exposed to 2-5 microM MX (2 h) showed an increased frequency of sister-chromatid exchanges (SCE) whereas no significant effect on HGPRT mutation induction was observed. Higher concentrations (greater than 10 microM, 2 h) apparently blocked cell division. The data indicate that MX can react directly with DNA or that MX is metabolized to an ultimate mutagen via some enzyme which is common in mammalian cells. The in vivo experiments showed no evidence of genotoxicity after intraperitoneal (18 mg/kg, 1 h) or oral (18, 63 or 125 mg/kg, 1 h) administration of MX, as measured by alkaline elution, in any of the following organs: the pyloric part of the stomach, the duodenum, colon ascendens, liver, kidney, lung, bone marrow, urinary bladder and the testes. In conclusion, MX is a direct-acting genotoxicant in vitro but no in vivo genotoxicity was detected.