Associations of CYP1A2 Polymorphisms with the Risk Haplotypes in Lung Cancer in the Slovak Population.

Phase I enzymes, including cytochrome P450, family 1, subfamily A, and polypeptide 2 (CYP1A2), are involved in the activation of carcinogens to reactive intermediates that are capable of binding covalently to DNA to form DNA adducts, potentially initiating the carcinogenic process. The aim of present study was to investigate the association of CYP1A2 gene polymorphisms and haplotypes with lung cancer risk. A case-control study was carried out on 105 lung cancer patients and 189 controls. To investigate three CYP1A2 polymorphisms: rs2472299, rs2470890, rs11072508 we used a high resolution melting analysis. We found significant allele associations (rs2470890 and rs2422299) with lung cancer risk. We searched for meaningful associations for all variants in the dominant, recessive, and additive genetic models. Genotype associations in the recessive model were of marginal significance for the same single nucleotide polymorphisms. A haplotype analysis included five variants with the frequency higher than 1 %. The haplotype "acc", present with the highest frequency, was associated with increased lung cancer risk (38.7 % vs. 31.5 %; OR 1.38; 95 %CI 0.95-2.01). On the contrary, rare haplotype "gtc" was significantly associated with decreased lung cancer risk in the Slovak population. In conclusion, the present study identified the risk alleles and haploid genotype associations of the CYP1A2 gene in lung cancer.

Non-invasive measurement of adrenocortical activity in male and female rats.

Rats are widely used in biomedical research as animal models for human diseases. However, due to their small body size, blood sampling is complicated and invasive and thereby can seriously interfere with endocrine functions and possibly compromise the animals' welfare. Therefore, a non-invasive technique to monitor stress hormones in these animals is highly desired. Our study aimed to gain general information about corticosterone metabolism and excretion and to validate a 5alpha-pregnane-3beta,11beta,21-triol-20-one enzyme immunoassay (EIA) to reliably measure faecal corticosterone metabolites (CMs) in laboratory rats. In total, 18 rats were administered 2.3 MBq of (3)H-corticosterone intravenously and per os, respectively (intravenous: 6 males and 6 females; per os: 3 males and 3 females). Subsequently, all voided excreta were frequently collected for five days. About 75+/-9% of the recovered CMs were found in the faeces. Peak concentrations of radiolabelled steroids appeared in the urine after 1.7+/-0.6 h in males and after 6.0+/-3.5 h in females. In faeces, maxima were observed after 14.7+/-2.4 h in both sexes. In principle, the time course and delay for both routes of administration (intravenous or per os) were the same, except for a delay of peak concentrations in urine (4.5+/-2.1 h) in per os administered males. Using high-performance liquid chromatography (HPLC), faecal (3)H-CMs were characterized and differences were found between the sexes. In both sexes, corticosterone was extensively metabolized, but while males showed only minor variations in their CM patterns, those of females differed largely between individuals. To validate the mentioned EIA, we investigated the diurnal variation (DV) of glucocorticoids as well as effects of the injection procedure itself and conducted an adrenocorticotropic hormone challenge test and a dexamethasone suppression test, using six male and six female rats each. Our results demonstrated that pharmacological stimulation, suppression and DV of adrenocortical activity were accurately reflected by means of CM measurement in faeces. By successful physiological validation, we proved for the first time the suitability of an immunoassay to non-invasively monitor adrenocortical activity in rats of both sexes. This method opens up new perspectives for biomedical and pharmacological investigations as well as for animal welfare related issues.

Ukrain: acute toxicity after intravenous, intramuscular and oral administration in rats.

The acute toxicity of Ukrain (1 g/30 ml) was determined after a single intravenous, intramuscular or oral administration in rats, performed in accordance with Good Laboratory Practice and the relevant European Community directive. Groups of five (male and/or female) Him:OFA rats were treated once with the following doses: intravenous route: 1.0 ml/kg (males and females), 1.7 ml/kg (males and females) and 3.0 ml/kg (females); intramuscular route: 5.0 ml/kg (males and females); oral route: 15.0 ml/kg (females), 27.0 ml/kg (males and females) and 50 ml/kg (females). The animals were kept for up to 14 days afterwards while clinical observations and body weight determinations were made and were then necropsied. An intravenous injection of Ukrain (1 g/30 ml) induced immediate effects (short-term unconsciousness, followed by cardiovascular signs and, later, signs of general malaise), which if not lethal, disappeared in a short time. It was found that the intravenous LD50 was greater than 43 mg active ingredient/kg body weight in the males and 76 mg active ingredient/kg body weight in the females. An intramuscular injection of Ukrain (1 g/30 ml) in the maximum technically feasible dose induced some transient signs of minor clinical importance which did not become life threatening. In both sexes the intramuscular LD50 was greater than 165 mg active ingredient/kg body weight.

Preliminary toxicokinetic study with different crystal forms of S (+)-ibuprofen (dexibuprofen) and R,S-ibuprofen in rats.

The aim of the study was to gain information on the plasma concentration-time profiles of both ibuprofen (CAS 15687-27-1) enantiomers in the rat after single oral application of two different crystal forms of S (+)-ibuprofen (dexibrufen, CAS 51146-56-6) and racemic ibuprofen in order to optimize blood-sampling times in a subsequent subchronic toxicity study. The application of either commercial racemic ibuprofen or recrystallised S (+)-ibuprofen (60 mg/kg) to two groups of 4 rats per blood sampling term was carried out in order to define Cmax and tmax and AUC of the plasma-concentrations of the ibuprofen enantiomers. The crystals of commercial (manufactured according to an usual manufacturing procedure) and recrystallised (S(+)- and racemic ibuprofen were different in respect to their shape and size. The recrystallised crystal species of S (+)- and racemic ibuprofen has better galenic (tabletting-) properties and tablets containing the modified S (+)-ibuprofen species showed favorable clinical results. The toxicokinetic behaviour of the recrystallised species was investigated in comparison to the commercial crystal species because of its slightly but significantly slower dissolution rate in simulated gastric and enteric juice. As the AUC0-24 h S-(+)-ibuprofen and the AUC0-24 h, R-(-)-ibuprofen after application of commercial and recrystallised crystal species were not different, the crystal form apparently did not exert an influence on the extent of absorption of S-(+)-ibuprofen and racemic ibuprofen in the rat. The rat has a high inversion capacity and the inversion of R-(-)-ibuprofen after application of commercial and recrystallised racemic ibuprofen was nearly complete in this study. The effects of crystallinity on solubility in simulated media in vitro did not correlate to the findings on the extent of absorption in the rat in vivo.

Bleomycin as carrier substance for 99m-Technetium in tumour diagnosis (author's transl). / Bleomycin als Trägersubstanz für 99m-Technetium in der Tumordiagnostik

99m-Tc-Bleomycin is a promising tool for scintigraphic imaging of some types of malignant tumours. The rapid decay of 99m-Tc, together with a high affinity of bleomycin for certain histologically-defined tumours recommends its use in humans. Moreover, by using high specific activities of bleomycin, no toxic effects are to be expected. At 00-C, the chelate of 99m-Tc and bleomycin is stable and its storage or transport are recommended at this temperature. Following the i.v. injection of rats with 99m-Tc-bleomycin, a high specific activity is found in the liver, spleen, lungs and skin. In view of its excretion by the kidneys an extremely high activity is found in the urogenital system. Scintigraphic imaging of lymph nodes in a case of Hodgkin's disease, of a embryonal carcinoma, of a thyroid carcinoma, of an astrocytoma and of a solid carcinoma was obtained in patients investigated by this method.