Behaviour of the Antitumor Agent Vanadocene Dichloride in Physiological and Therapeutic Media, Blood Plasma and Human Blood - An EPR Study

By means of EPR spectroscopy the behaviour of the vanadocene dichloride (I), Cp(2)VCl(2) (Cp=eta(5)-C(5)H(5)), in various deoxygenated and non-deoxygenated physiological media and therapeutic solution as well as in blood plasma and stabilized human blood was studied. On the basis of measured values of isotropic spectroscopic splitting factor g(iso) and isotropic hyperfine coupling constant A(iso), the vanadocene species, [Cp(2)V(H(2)O)Cl](+) (II; g(iso)= 1.985, |A(iso)| = 7.68 mT), [Cp(2)V(H(2)O)(2)](2+) (III; g(iso)= 1.983, |A(iso)| = 7.92 mT), [Cp(2)V(OH(2) (IV; g(iso)= 1.991, |A(iso)| = 6.285 mT), [Cp(2)VCl(DMSO)](+) (V; g(iso)= 1.985, |A(iso)| = 7.69 mT), the vanadyl species [VO(DMSO)(5)](2+) (VI; g(iso)= 1.964, |A(iso)| = 10.78mT) and [VO(H(2)O)(5)](2+) (VII; g(iso)= 1.955, |A(iso)| = 11.56 mT) have been identified. From the measurements it follows that I does not react in its first coordination sphere with any component of a system used other than water and DMSO, resp. As to water-containing media, its behaviour is fully consistent with that of I in pure aqueous media. It was found the only vanadocene species present after application of the therapeutic solution of I into human blood to be IV not interacting in its first coordination sphere with any blood component.     

Variation in fatty acid composition of ewes' colostrum and mature milk fat

Temporal content variations of approximately 70 C4–C24 fatty acids (FA) in colostrum and milk of ewes consuming winter diet were determined by gas chromatography. The content of monounsaturated, polyunsaturated and straight-chain saturated FA 14:0–16:0 in colostrum was higher whereas the content of 4:0–12:0, 18:0 and branched-chain saturated FA 15:0–17:0 was lower than that in mature milk. The effect of ewe breed on the FA profiles was not significant. The composition of FA changed most significantly 1–2 days after lambing in agreement with the time schedule of colostrum formation. Nevertheless, the content of FA further successively changed up to approximately the 6th day of lactation, whereas further changes up to the 60th day of lactation were smaller. This is consistent with the recommendation that ewes' milk is suitable for human consumption after six-to-eight days of lactation. The higher contents of palmitic and myristic acids in colostrum compared with mature milk suggest that FA composition in colostrum matches the changing needs of the growing lambs.     

Experimental Investigation of the Properties of Lime-Based Plaster-Containing PCM for Enhancing the Heat-Storage Capacity of Building Envelopes

Experimental analysis of a wide range of properties of a lightweight plaster which should enhance the heat-storage capacity of building envelopes is presented. The basic physical characteristics, namely, the bulk density, matrix density, total open porosity, and pore-size distribution are measured at first. Then, the compressive strength is determined for an assessment of mechanical performance of the plaster. The thermal conductivity and thermal diffusivity are studied using an impulse technique. Differential scanning calorimetry measurements are performed as well, in order to identify the temperature range and latent heat of the phase change and to determine the specific heat capacity as a function of temperature. Durability properties are assessed using the measurement of the water absorption coefficient and sorption and desorption isotherms. The experimental results indicate a good capability of the designed plaster to moderate effectively the interior climate of buildings.     

Variation in fatty acid composition of ewes' milk during continuous transition from dry winter to natural pasture diet

The profile variations of approximately 70 fatty acids (FAs) in milk of ewes consuming total mixed rations (TMR) and grazing natural pasture were determined. Milk of ewes grazing pasture in May and September in the Slovak Republic contained 3-times more conjugated linoleic acid (CLA) (P < 0.001) and trans-vaccenic acid (TVA) (P < 0.001), and 2-times more α-linolenic acid (ALA) (P < 0.001) than that of ewes fed TMR. A doubling of the CLA and TVA contents of milk of ewes fed with TMR was achieved by changing to meadow hay containing a higher ALA content. Less availability of vegetation and lower ALA pasture content in summer (P < 0.001) caused a 2-fold decrease (P < 0.001) of CLA and TVA contents when compared with data obtained in May. With grass re-growth and an increase in pasture ALA content in September, the CLA and TVA contents rose to values similar to those obtained in May (P > 0.05). No significant differences in the FA composition in milk of ewes grazing on summer pasture at higher altitude were observed.     

Conditionally pathogenic mycobacteria in the environment and their effect on living organisms

Since 1968 when bovine tuberculosis was eliminated in the Czech Republic, the epidemiological situation of bovine tuberculosis has been stabilized. At present the incidence of the disease in men and animals caused by conditionally pathogenic mycobacteria is worldwide increasing. In human population, especially people with impaired immunity are affected. In farm animals infections caused by conditionally pathogenic mycobacteria may often result in complications in intravital and postmortal diagnosis of bovine and avian tuberculosis. Those infections are then often incorrectly diagnosed which could have a great negative impact on health, economy and breeding. Therefore the objective of the study was to summarize data from literature and our own experience concerning the occurrence of atypical mycobacteria in environment. The study is divided into 5 summarizing chapters, supplemented with 13 Tables.     

Theoretical and Experimental Analysis of Moisture-Dependent Thermal Conductivity of Lightweight Ceramic Bricks

The moisture-dependent thermal conductivity of two types of lightweight ceramic brick body is analyzed using both theoretical and experimental approaches. The basic physical properties are determined at first. Then, an impulse method is applied for the thermal-conductivity measurement. Initially, the material samples are dried, after that, they are exposed to liquid water for specific time intervals, and finally the moisture content is allowed to homogenize within the whole volume. The thermal-conductivity measurement is performed for different moisture contents achieved in this way. In the theoretical part, the homogenization principles are used for the calculation of the moisture-dependent thermal conductivity, utilizing the distribution functions based on the pore-size distribution measurement. Finally, a comparison of the measured and calculated data is done, and the validity of the applied effective media treatment is assessed.     

Spontaneous Cryptosporidium infection in weaned rabbits

The first occurrence of Cryptosporidium parvum Tyzzer, 1912 in broiler rabbits in the Czech Republic is reported. The protozoon was determined on the basis of morphometrical parameters of oocysts and of localization of endogenous developmental stages. The dynamics of natural Cryptosporidium infection was studied in a group of 72 young rabbits after weaning (their age ranging from 23-33 to 82-92 days) obtained from six large flocks and used in a feeding experiment. C. parvum was found in rabbits from four farms (Tab. I). Animals under observation were divided into 9 subgroups according to the genotype (Hyla 2000, California White, crosses of New Zealand x California, New Zealand White, Cunistar and Zika) as well as according to the farm of origin. The animals were housed in 28 cages under the conditions of two-floor cage technology. The upper floor consisted of cages housing three head, the lower floor two head each. The animals were fed ad libitum with commercial feed mixture (till the average age of 64.days supplemented with Robenidin as coccidiostat). During the first 10 days of observation pooled samples of droppings from each cage were examinated by flotation-centrifugation method according to Breza (1957) and Pavlásek (1991) in the intervals of three to four days, later one-week intervals. Post mortem scrapings from mucous epithelium taken from young rabbits were examinated (to reveal endogenous developmental stages of C. parvum) together with digesta (to detect oocysts of the protozoon) taken from the full length of the small intestine using method of native preparations and Giemsa stain. In one 37-day dead animal the small and large intestines were examined histologically. The maximum number of young rabbits infected with C. parvum were 30-40 and 33-43 days old (Fig. 1). In animals of this age category the oocysts of the protozoon were found in pooled samples in 11 and 12 cages (39.3 and 42.9%) from totally 28 cages under study. In rabbits of more than 50 days of age the occurrence of infection was significantly decreased (3.7%). During the experiment seven rabbits (9.7%) died; six of them (8.3%) at the age of 30-40 days. All these naturally infected and dead animals represented cases of monoinfection with C. parvum. The major clinical signs were typical diarrhoea lasting 3-5 days, inappetency, apathia, lethargy, prominent signs of exhaustion followed by dehydration of the organism. Atrophy of villi of the ileum in one of young rabbits was found histologically. Table II presents concrete data on significantly lower body weights (the decrease being 7-61.5%) as compared with rabbits of the same age not infected with cryptosporidia. It was not possible to evaluate objectively the differences in susceptibility to C. parvum infection between the individual genotypes of rabbits. As was found in the course of our further studies (unpublished data) a possible source of infection of young rabbits can be represented by their mothers in which oocysts are excreted sporadically shortly before parturition and during several days after it. Cryptosporidium infection (cryptosporidiosis) in flocks of broiler rabbits is taken as a new protozoal disease in the Czech Republic and C. parvum as one of possible agents in cases of disorders of digestive tract, namely in rabbits after weaning.     

Paroxysmal nocturnal hemoglobinuria and its association with aplastic anemia

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder of haematopoiesis. Clinically it is characterized by intravascular haemolysis, venous thrombosis and often by bone marrow hypoplasia. Haemolysis and thrombosis develop as a consequence of deficiency of several proteins on the cell membrane of the affected clone of blood elements. This is caused by somatic mutations in the PIG-A gene, which encodes an enzyme involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchor. Spectrum of mutations in the PIG-A gene is different to that observed in other genes. The mutations are mainly small deletions and insertions causing frameshift; large deletions are rare. Recently, however, a 88 base pairs direct tandem repeat insertion has been reported in a patient with PNH developed on the background of aplastic anaemia (AA). The peculiar pattern of the PIG-A gene mutations and the finding that more than one mutated clone is commonly present in patients with PNH might suggest that some form of hypermutability, caused by decreased DNA stability, deficient repair or increased generation of mutagens, might underline PNH. As most mutations cause cell death, it would explain the hypoplastic nature of the disorder and its association with AA. Other models of pathogenesis of PNH are also discussed.     

Serum- and bradykinin-induced calcium transients in familial Alzheimer's fibroblasts

The calcium-sensitive photoprotein, aequorin, was used to examine serum- and bradykinin-induced transient increases in free cytosolic calcium ions in skin fibroblasts from 10 individuals with early onset familial AD (FAD), including four who were biopsied before their clinical symptoms would allow a diagnosis of AD, 2 individuals with late onset FAD, 8 at-risk but nonsymptomatic individuals, and 13 controls. The data show that (a) among controls, the peaks of the calcium transients increase in height as a function of donor age; (b) transients induced by 10% serum, 10 nM bradykinin (BK) or 100 nM BK were generally lower in FAD fibroblasts, including those from donors in the early stages of the disease, than in age-matched control cells; (c) such transients are reduced in cells from a proportion of the nonsymptomatic, at-risk individuals. Thus, serum- and BK-induced calcium transients are reduced in fibroblasts from both early and more advanced stage FAD donors and perhaps even from donors who are presymptomatic carriers of the defective gene. The data also suggest that changes in calcium transients in FAD fibroblasts neither mimic nor exaggerate the effects of normal aging.