А rare case of primary malignant melanoma of the female urethra.

Primary malignant melanoma of the female urethra is an extremely rare disease. Its frequency is only 0.2% of all malignant melanomas. This type of carcinoma is associated with a poor prognosis and short survival due to the early occurrence of metastases and delayed diagnosis. We present a patient with primary malignant melanoma invading the distal urethra, part of the labia minora, and sections of the anterior vaginal wall, where 15 months of overall survival were achieved against the background of the complex treatment.

Differential expression of neural-cadherin in pulmonary epithelial tumours.

AIMS: Neural (N)-cadherin belongs to a group of transmembrane molecules with a crucial role in tissue morphogenesis and maintenance of an epithelioid phenotype and increased N-cadherin expression is implicated in tumour progression and dedifferentiation. The aim was to determine whether evaluation of N-cadherin in pulmonary tumours might assist in identifying lesions with more aggressive potential. METHODS AND RESULTS: One hundred and fifty-five pulmonary lesions were analysed for N-cadherin expression using immunohistochemistry, including neuroendocrine hyperplasia (n = 3), typical carcinoid (n = 59), atypical carcinoid (n = 12), small cell lung carcinoma (n = 11), large cell neuroendocrine carcinoma (n = 12), adenocarcinoma (n = 35) and squamous cell carcinoma (n = 23). Lymph node status was correlated with immunohistochemical expression. N-cadherin expression was demonstrated in all cases of neuroendocrine hyperplasia, 96% of typical carcinoids, 83% of atypical carcinoids, 63% of the small cell lung carcinomas and 32% of large cell neuroendocrine carcinomas. Over 90% of the adenocarcinomas and 100% of the squamous cell carcinomas were negative. Increased N-cadherin expression in typical carcinoids was associated with negative lymph node status (P < 0.001). DISCUSSION: N-cadherin is differentially expressed in pulmonary tumours and is predominantly observed in neuroendocrine lung lesions with high expression in typical and atypical pulmonary carcinoids. The level of expression of N-cadherin between types of lung tumours does not appear to indicate malignant potential or aggressive behaviour.

Traceability from weathered oil spills in the marine environment to the original contamination source. A case study.

An algorithm for stepwise approximation to the most reliable source of contamination is proposed. The concept of the algorithm is based on discrimination rather than on similarity. Gradually, by means of more complicated and higher distinguishing power approaches, the differences between the spilled sample and the suspected source are checked. Capillary gas chromatography with flame-ionization and mass spectrometric detection was applied to gather the necessary data. Fingerprint, diagnostic parameter approaches and pattern recognition methods were used for reliably distinguishing the analytical results. If the compared samples are not discriminated by any means, they are considered as identical.

Experimental model for optimization of hydrophobic interaction: chromatographic purification of glucagon.

The chromatographic behavior of the components of glucagon-containing material from bovine pancreas by hydrophobic interaction on Amberlite XAD-7 was investigated. The effect of initial ionic strength and pH of the mobile phase on selectivity was quantitatively determined. The data, obtained from 56 experiments, were used for modeling and the corresponding management of the purification process. The purified glucagon is of very high quality: total impurities are not more than 1.7% as determined by analytical HPLC. The biological activity is 1.08 IU/mg, calculated for dry substance.

Effect of mobile phase composition on selectivity in preparative hydrophobic interaction chromatographic purification of glucagon.

A weakly hydrophobic acrylester copolymer, Amberlite XAD-7, has been used in the purification process of glucagon production for elimination of protein impurities in the crude glucagon fractions, obtained from the industrial waste from insulin production. Varying the mobile phases composition, it was shown that suitable selectivity for the separation of proteins under non-denaturing conditions can be achieved. The purified glucagon, obtained at the proposed chromatographic conditions has a biological activity of above 1 IU/mg.

Experimental models for optimization of insulin separation on reversed phase columns.

Experimentally defined relationships have been found to describe adequately the retention and separation of bovine and porcine insulins as well as their desamido products on reversed phases C4 30 nm and C18 10 nm pore diameter. The equations are valid for a region of initial acetonitrile concentrations from 16 to 31% and gradient rates from 0.04 to 0.60%/min. The peak heights showed an exact non-linear relationship with the time interval between the first and last peak of interest, independent of their retention time. The number of experiments required for obtaining the parametric estimates of the models depends on the particular task, but in all cases is less than eight. The relationships found permit the correct choice to be made in advance both for analysis conditions for a particular column and for different requirements of insulin analysis.

Purity evaluation of aprotinin by high performance liquid chromatography.

A separation to the baseline isocratic technique has been developed for the evaluation of the purity of aprotinin by internal normalization. The column used was a 30 nm pore diameter butyl-bonded silica stationary phase. An exact relationship was found to give an adequate description of the retention of aprotinin using acetonitrile concentrations of 17-22% and NaClO4 concentrations of 5-50 mmol. It can be used to optimize the mobile phase content for the particular user column and to compensate for possible variations in the retention time of aprotinin, analysed on different batches of butyl-bonded stationary phases.

[Comparative evaluation of several noninstrumental methods of determining fats in the fermentation media in manufacturing antibiotics]. / Sravnitel'naia otsenka neskol'kikhh neinstrumental'nykh metodov opredeleniia zhirov v fermentatsionnykh sredakh pri proizvodstve antibiotikov.

The use of instrumental analysis (IR spectrometry, high performance liquid chromatography) for determination of fats in the nutrient media and fermentation broths in antibiotic production is not efficient. 7 noninstrumental methods for determination of fats in the fermentation broths of some fat-soluble polyester antibiotics were compared. The first method includes extraction of the fermentation broth with different agents, gravimetric estimation, measuring of the saponification number and refraction coefficient and thin-layer chromatography. It was shown that determination of the saponification number after extraction with alkanes or diethyl ether provided reliable results. Thin-layer chromatography can be used as a rapid method.