Serum paraoxonase activity in dairy cows during pregnancy

Preparturient dairy cows are at high risk of metabolic and reproductive disorders and oxidative stress is considered to be involved in these events. We investigated the serum paraoxonase activity in dairy cows during pregnancy and alterations in lipid and lipoprotein patterns in this period. The relation between paraoxonase activity and HDL-cholesterol concentration was also compared. The study was carried out on 76 pregnant lactating and 26 pregnant dry Holstein dairy cows. The serum paraoxonase activity was determined by the method of hydrolysing of paraoxon, while triglyceride, cholesterol and HDL-cholesterol concentrations were measured by the enzymatic kit methods. A significantly higher serum triglyceride concentration (P<0.001) was observed in dry cows compared to lactating cows. The total cholesterol and HDL-cholesterol concentrations were significantly lower (P<0.001) in dry cows than in lactating ones. In dry cows, paraoxonase activity was significantly lower than in those lactating (P<0.001). There was no significant difference in paraoxonase/HDL-cholesterol ratio between the investigated groups. It seems that the lower HDL concentration could be one of the causes of reduced paraoxonase activity considering the role of HDL as a carrier of most paraoxonase molecules in the blood. A decreased serum paraoxonase activity could diminish the effectiveness and total capacity of the whole antioxidative system during prepartum period in dairy cattle.     

Third coronary artery in monkey heart

Investigations were carried out on 55 monkey (Cercopithecus aethiops, Macaca fascicularis) hearts by stereomicroscopic dissection and measurements. Latex-injected specimens and corrosion casts showed that, as in humans, the hearts were usually (in 98.2% of the cases) supplied by two coronary arteries (CAs)--the left (LCA) and the right coronary artery (RCA), and occasionally (in 1.8% of the cases) also by a third one (TCA). Furthermore, the orifice of the TCA was situated in the right aortic sinus at the same level as the RCA and 0.2 mm in front of it. The LCA and the RCA originated from the corresponding aortic sinuses and the external diameter of the LCA was greater [average: 1.65+/-0.39 (SD) mm] than that of the RCA [average 0.94+/-0.15 (SD) mm] and the TCA (0.8 mm). The LCA orifice was more often above (76.3%) than below the free edge of the left aortic valve leaflet. The longitudinal axis of the aortic root and of the initial part of the LCA formed an angle of 45-120 degrees (average: 52 degrees). The orifice of the RCA was usually above (82.3%) the free edge of the right aortic valve leaflet, and less frequently below it (17.7%). The longitudinal axis of the aortic root and of the initial part of the RCA formed an angle of 70-150 degrees (average: 103 degrees). The resemblance of monkey CAs to their human counterparts make them a suitable model for experimental studies on coronary circulation.     

Differentiation and developmental potential of rat post-implantation embryo without extra-embryonic membranes cultured in vitro or grafted in vivo

Different experimental systems are used to study developmental processes in mammals. In this study, three experimental models were analysed and correlated: (1) cultivation of rat embryos in vitro; (2) cultivation in vitro and then transplantation in vivo; (3) direct transplantation in vivo. When embryos were cultivated in vitro and then transplanted in vivo, after the initial in vitro restriction, developmental potential was recovered. The in vitro restriction depended on medium used and duration of culture. Pre-cultivation in serum-free medium for 7 days restricted developmental potential for nervous tissue, and for 14 days restricted developmental potential for skeletal muscles, adipose tissue and glandular epithelia. Transferrin addition improved in vitro differentiation of neuroblasts, cartilage and columnar epithelium. In the combined in vitro and in vivo method, transferrin preserved developmental potential in comparable extent to the addition of the serum. Even in serum-free conditions in vitro, the subsequent in vivo wide expression of developmental potential was possible. Therefore, the combination of in vitro and in vivo methods turned to be advantageous than the isolated approaches (in vitro or in vivo only), and enabled testing in more detail the influence of a single substance on developmental course and potential.     

The relaxant effect of vasoactive intestinal polypeptide in the isolated canine uterine artery: the role of endothelium

The purpose of this study was to examine the effect of vasoactive intestinal polypeptide (VIP) on the uterine artery obtained from non-pregnant dogs. VIP (3 x 10(-9)-3 x 10(-7) M) induced concentration-dependent relaxation in canine uterine arteries with intact endothelium, pre-contracted with 10(-5) M phenylephrine (pEC(50) = 7.52 +/- 0.02, maximal response was 82.19 +/- 2.15%, n = 36). The administration of the cyclooxygenase inhibitor indomethacin (10(-5) M) or 4-aminopyridine (4-AP), a blocker of potassium channels (10(-5) M), did not modify the relaxation induced by VIP. Contrary to this, N(G)-nitro-L-arginine (L-NOARG) (10(-5) M) inhibited relaxation is evoked by VIP. Indomethacin applied with L-NOARG did not provoke further inhibition of VIP-induced relaxation. In the presence of both L-NOARG and L-NOARG + indomethacin, 4-AP led to the further inhibition of VIP-induced relaxation of canine uterine artery. It is concluded that VIP induces endothelium-dependent relaxation of uterine arteries of non-pregnant dogs, which can be entirely explained by the production of nitric oxide (NO) from the endothelial cells. We proposed that when NO synthesis is inhibited, VIP induces further relaxation, independent of the edothelium-derived relaxing factors, probably through activation of K(+) channels.     

Periparturient endocrine and metabolic changes in healthy cows and in cows affected by mastitis

Transition from pregnancy to lactation in dairy cows involves considerable metabolic adaptation. Additional stress is incurred during infections such as periparturient mastitis. Multiparous Holstein-Friesian cows kept under normal production conditions (n = 15) were used to evaluate changes in circulating metabolite and hormone concentrations from 5 days before to 5 days after calving. Insulin-like growth factor binding protein (IGFBP) profiles were also monitored. Marked time-related changes were observed for plasma thyroid hormone, IGF, cortisol, insulin, beta-hydroxybutyrate (BHB) and non-esterified fatty acid (NEFA) concentrations but not for plasma leptin. A decrease in IGF-II concentration and maximal intensity of the putative IGFBP-1 band occurred at parturition. When compared with the five healthy cows,low IGF-II levels were prolonged to day 2 post-partum in five cows with Escherichia coli-associated mastitis. However, marked decreases in IGFBP-2 band intensity were evident only in two of the four cases examined. Individual total ligand (IGF-I + IGF-II) concentration and IGFBP pattern prepartum were largely regained 5 days post-partum in all cows. Hormone and metabolite concentrations in the two cows with Staphylococcus aureus-associated mastitis were very similar to those in the five healthy cows. Plasma thyroxine (T4) was lower 2 days prepartum in the cows, which later developed Gram-negative mastitis. Multiregression analysis showed that variance in T4 concentration was significantly and independently associated with triiodothyronine (T3) and IGF-I positively and with cortisol negatively (R2 = 0.648). This study confirms the close inter-relationship between the thyroid hormone and IGF axes in cattle and indicates possible effects of Gram-negative mastitis infection on IGF-II metabolism.     

Short-term effect of acarbose on specific intestinal disaccharidase activities and hyperglycaemia in CBA diabetic mice

The purpose of this study was to examine the short-term effects of 75, 100 and 150 mg of acarbose mixed in 100 g standard laboratory chow on specific intestinal disaccharidase activities and on hyperglycaemia in diabetic CBA strain mice on standard diet. The small intestine was excised and divided into three segments, from pylorus to duodenum, and two equal lengths of the jejunum and ileum of control and diabetic mice with or without added acarbose. Specific maltase and sucrase activities were determined using maltose and sucrose as substrates respectively. Increased specific activities of maltase and sucrase were detected in the intestines of CBA mice on standard laboratory diet seven days after alloxan-induced diabetes. Feeding for 7 days with 75, 100 or 150 mg acarbose uniformly mixed in 100 g standard laboratory chow, induced a decrease in the specific maltase and sucrase activities, compared with diabetic mice on standard laboratory diet. Feeding with 75 mg acarbose mixed in 100 g standard laboratory chow caused a statistically significant decrease of maltase in the duodenum and of sucrase in duodenum and jejunum, without a antihyperglycaemic effect. Feeding with 100 or 150 mg caused statistically significant decreases in specific maltase and sucrase activities in duodenum, jejunum and ileum. An antihyperglycaemic effect was observed only in the group of diabetic mice fed with 100 mg acarbose. This indicates that the antihyperglycaemic effect of acarbose involves factors other than these, related only to its inhibitory effect on disaccharidase activities.     

Genetic typing of recent classical swine fever virus isolates from Croatia

During a period of 5 years (1997-2001) several outbreaks of classical swine fever (CSF) were recorded in Croatia. For genetic typing, fragments of 150 nucleotides within the 5'-non-translated region (5'-NTR) and 190 nucleotides within the E2 glycoprotein coding gene of nine field isolates that were derived from domestic pigs and wild boars were used. For better epizootiological understanding, isolates from other European countries were included in the study. The results show that the isolates belong to subgroups 2.1 and 2.3 of CSF virus. Isolates from subgroup 2.1 were collected from domestic pigs during sporadic outbreaks in June 1997 and are genetically closely related. A genomic similarity between these isolates and CSF virus isolates from pigs in other European countries from the same year could also be confirmed. In contrast, the isolate from October 1997 was found to be a member of subgroup 2.3, and is closely related to European CSF virus isolates from outbreaks in the last decade in Western and Central European countries. These results show that two different sources of CSF virus caused outbreaks in Croatia during the same year. Furthermore, a close relationship was found between an isolate from a domestic pig in 1999 and isolates of subgroup 2.3 that originated from Croatian wild boars.     

Newcastle disease antibody titre is dependent on serum calcium concentration

Chickens were fed diets having optimal, high, and low levels of calcium for 42 days. Serum samples were collected at 14, 28 and 42 days of age, and serum calcium and haemagglutination inhibition titres for Newcastle disease virus were measured. The chickens were vaccinated at 14 days for Newcastle disease. Antibody titres were significantly increased by high dietary calcium and depressed by low dietary calcium. Mean titre was 2.5 (log2) for the optimal diet, 3.2 for the high-calcium diet, and 1.6 for the low-calcium diet. Antibody titres were dependent on serum calcium concentration (r2 = 0.98 at 14 days, 0.99 at 28 days, and 0.78 at 42 days).     

Defence Responses Against TNV Infection Induced by Galactoglucomannan-derived Oligosaccharides in Cucumber Cells

Galactoglucomannan-derived oligosaccharides (GGMOs) showing biological activity in growth, morphogenesis and cell viability were tested in a host pathogen interaction. As a model system, cucumber (Cucumis sativus L. cv. Laura) reacting hypersensitively to tobacco necrosis virus (TNV) was used. The defence reactions were dependent on the degree of polymerisation and concentration of oligosaccharides, as well as on the time of application of virus to plant cotyledons. Disease symptoms were inhibited by 60–75%. The average number of lesions per cotyledon was significantly decreased when oligosaccharides were used simultaneously or 24h prior to virus inoculation. Significant changes in peroxidase, beta-glucanase and chitinase activities accompanied the defence reaction. It can be concluded that oligosaccharides derived from spruce galactoglucomannan induce non-specific resistance to local viral infection in plants. GGMOs probably act as inhibitors of the virus infection, rather than inhibitors of direct virus multiplication.