UV induced erythema evaluated 24 h post-exposure by skin reflectance and laser Doppler flowmetry is identical in healthy persons and patients with cutaneous malignant melanoma and basal cell cancer

Twenty-one patients with invasive cutaneous malignant melanoma and 19 patients with basal cell skin cancer and 29 healthy volunteers were phototested on non-UV exposed buttock skin to examine their 24 h reaction to a series of increasing doses of simulated sunlight with 25% dose increments. Skin pigmentation at the phototest sites was determined by skin reflectance before testing to assure an equal level of constitutive skin pigmentation in the 3 groups. Erythema reactions were scored visually 24 hours post-exposure and objective measurements of erythema were performed by skin reflectance and laser Doppler flowmetry. In adjacent non-irradiated skin the redness was also quantified to determine the increase in redness in irradiated skin compared to non-irradiated skin. Constitutional skin pigmentation correlated well to UV sensitivity (r = 0.75) and skin redness measured by skin reflectance technique correlated to laser Doppler flowmetry (r = 0.86). No significant differences in UV doses to barely perceptible erythema or to the higher erythema grades were found between the two skin tumour groups and the control group, and no significant differences were found in skin reflectance measured redness or in laser Doppler flowmetry of any erythema reactions between the 3 groups. The 24 h erythema reaction to sunlight can therefore not be used to distinguish patients with invasive cutaneous malignant melanoma or basal cell carcinoma from normal persons.     

Sister-chromatid exchanges in lymphocytes in women with cancer of the breast

Examination of sister-chromatid exchanges (SCE) in lymphocytes may be useful for the evaluation of exposure to mutagens/carcinogens. Information of a possible association between SCE and cancer is scarce. We therefore examined SCE in peripheral lymphocytes in 131 women, aged 17-90 years (median 51.8 years), coming to operation because of a tumor of the breast. Venous blood samples were cultivated during PHA stimulation in the presence of BrdU. After treatment with colcemid (R), fixation, treatment with bisbenzimide and staining with Giemsa, 30 metaphases were scored in each specimen. 52 patients with peroperatively demonstrated carcinoma of the breast had 9.39 +/- 0.17 SCE/cell and the remaining 79 women with non-malignant fibroadenomatosis had 9.88 +/- 0.18 SCE/cell. By multiple regression analysis it appeared that the character of the tumor, the patient's age, hormone treatment and preoperative examination by mammography all were without significant influence on the SCE rate. A statistically significant correlation was found between SCE and cigarette smoking. THe 45 cigarette-smoking patients had 10.49 +/- 0.23 SCE/cell compared with 9.26 +/- 0.13 SCE/cell in the 86 non-smokers. It was concluded that spontaneous SCE in lymphocytes is not an indicator of carcinoma of the breast.     

The Oregon Report Software Engineering: The Turning Point

In 10 years, the pursuit of software engineering has produced a wealth of good ideas. The time has come to put them to work.     

Volatile halogenated hydrocarbons in Belgian drinking waters

A comparative study was carried out to determine levels of volatile halogenated hydrocarbons, especially trihalomethanes (THM) in different Belgian drinking waters, prepared from both ground and surface waters. In addition to examining raw and treated water leaving the production plants, changes in haloform concentration during transport in the distribution system were also studied. Only a slight decrease of haloform concentration after decompression in water towers and reservoirs occurred and was rapidly compensated by on going chlorination by residual free chlorine.Despite of the very different conditions used for chlorination in the plants studied, a fairly clear relation was found between total THM content in the finished waters and TOC-values of the raw waters, indicating that the primary organic load was the determining factor for haloform formation.     

Organic matter preservation in the sediment of an acidic mining lake

Sustainable management of acidic mining lakes requires knowledge on the origin and reactivity of its sedimentary organic matter. We identified different pools of organic matter (OM) in the Fe-rich sediment (up to 35 wt %) of an acidic (pH 2.8) mining lake using delta13C-signals, C/N ratios, and the markers alkanes, lignin-derived phenols, and benzenepolycarboxylic acids (BPCA). Additionally, a density fractionation was applied to each sediment layer. Three fractions, aquatic (AOM), terrestrial (TOM), and lignite-derived (LOM) organic matter, were discriminated, of which AOM comprises only a small fraction, with a minimum at the sediment bottom. The terrestrial contribution to sedimentary OM is higher than that of AOM but still low throughout the sediment core, whereas lignite-derived OM constitutes the major C-fraction, even in the upper sediment layers. The size of the carbon pools was quantified with a mass-balance approach, in which the BPCA content was utilized as an estimate for the lignite fraction in combination with the delta13C-signals of the three C fractions. The largest amount of OM was found in the heaviest (>2.4 g cm3) of the three density fractions of the two upper sediment layers, which implies strong interaction with iron hydroxides. Comparisons with C-oxidation rates revealed that besides the refractory origin of the OM, sorptive preservation by solid iron phases controls C-reactivity in the sediment and, hence, the internal neutralization capacity of the lake system.     

Metal Ion‐Terpyridine‐Functionalized L‐Tyrosinamide Aptamers: Nucleoapzymes for Oxygen Insertion into C?H Bonds and the Transformation of L‐Tyrosinamide into Amidodopachrome

A series of metal ion‐terpyridine‐modified L‐tyrosinamide aptamers (M^{n +} = Cu²⁺ or Fe³⁺) act as enzyme‐mimicking catalysts (nucleoapzymes) for oxygen‐insertion into C? H bonds and the transformation of L‐tyrosinamide into amidodopachrome. The reaction proceeds in the presence of H₂O₂ and coadded L‐ascorbic acid. In one series of experiments, the catalyzed oxidation of L‐tyrosinamide to amidodopachrome by a set of nucleoapzymes consisting of Fe³⁺‐ or Cu²⁺‐terpyridine complexes tethered directly or through a 4 × thymidine (4 × T) bridge, to the 5′‐ or 3′‐end of the 49‐mer L‐tyrosinamide aptamer or to a shorter 23‐mer L‐tyrosinamide aptamer is examined. All nucleoapzymes reveal catalytic Michaelis–Menten enzyme‐like activities and the separated Fe³⁺‐ or Cu²⁺‐terpyridine and L‐tyrosinamide aptamer units show only minute catalytic properties. The catalytic activities of the nucleoapzymes are attributed to the concentration of the L‐tyrosinamide substrate by the aptamer units in proximity to the catalytic sites (K_d = (14 ± 0.1) × 10^?6 m for all 49‐mer catalysts and K_d = (2.5 ± 0.1) × 10^?6 m and K_d = (0.8 ± 0.04) × 10^?6 m for the 23‐mer catalysts). Electron spin resonance experiments reveal that ?OH radicals and ascorbate radicals participate in the transformation of tyrosine derivatives to catechol products. An autocatalytic feedback mechanism for the amplified generation of the two radicals is suggested.