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1.
The influence of temperature (10 degrees C and 20 degrees C) on pharmacokinetics and metabolism of sulphadimidine (SDM) in carp and trout was studied. At 20 degrees C a significantly lower level of distribution (Vdarea) and a significantly shorter elimination half-life (T(1/2)beta) was achieved in both species compared to the 10 degrees C level. In carp the body clearance parameter (ClB(SDM)) was significantly higher at 20 degrees C compared to the value at 10 degrees C, whereas for trout this parameter was in the same order of magnitude for both temperatures. N4-acetylsulphadimidine (N4-SDM) was the main metabolite of SDM in both species at the two temperature levels. The relative N4-SDM plasma percentage in carp was significantly higher at 20 degrees C than at 10 degrees C, whereas there was in trout no significant difference. In neither species was the peak plasma concentration of N4-SDM (Cmax(N4-SDM)) significantly different at two temperatures. The corresponding peak time of this metabolite (Tmax(N4-SDM)) was significantly shorter at 20 degrees C compared to 10 degrees C in both carp and trout. In carp at both temperatures, acetylation occurs to a greater extent than hydroxylation. Only the 6-hydroxymethyl-metabolite (SCH2OH) was detected in carp, at a significant different level at the two temperatures. Concentrations of hydroxy metabolites in trout were at the detection level of the HPLC-method (0.02-micrograms/ml). The glucuronide metabolite (SOH-gluc.) was not detected in either species at the two temperatures.  相似文献   
2.
1. Bedouin chickens are kept in deserts mainly for eggs and are well adapted to arid conditions. However, deserts are also characterised by relatively cold winter nights. As a consequence of cold stress there is an involution of lymphoid organs and a depression of immunological function. We compared the performance and immunological responses of Bedouin and White Leghorn hens kept in outdoor pens in the Negev Desert during the winter.

2. Initial mean body mass was similar for the two breeds: 1525 g for Bedouin hens and 1542 g for White Leghorn hens. White Leghorns lost 7–74 g/d, compared with 0.60 g/d for Bedouin hens and produced 0.36 eggs/d, compared with 0.54 eggs/day for Bedouin hens.

3. The heterophil/lymphocyte ratio for Bedouin hens was 0.28, which was lower than the 0.44 for White Leghorn hens. Phagocytic index was higher in Bedouin hens than in White Leghorns. Furthermore, wattle index measured 24, 48 and 72 h after PHA injections and anti‐SRBC antibody titres determined 10 d after challenge were also higher in Bedouin hens than in White Leghorns.

4. We concluded that the Bedouin hens were less stressed by the cold than were the White Leghorn hens.  相似文献   

3.
1. The effect of warmed drinking water on the performance and immunological responses of broiler breeder hens maintained at low air temperatures (5.0° to 12.9°C) was tested. From 22 weeks of age hens (mean body mass = 2.4 kg) were offered either warm water (27.7°C; WARM; n=24) or tap water (12.7°C; CONR; n=24) twice daily for a total time of 2.5 h or tap water ad libitum (CONA; n = 16). Food was restricted for all hens.

2. Daily water intake in the WARM hens (103 ml/kg) was similar to that of the CONR (93 ml/kg) and CONA hens (106 ml/kg).

3. There were no significant differences in either body mass change or egg production among treatment groups.

4. There was no difference among groups in heterophil/lymphocyte ratios. Similarly, there was no difference among groups in either phagocytic activity or wattle index after phytohaemagglutinin (PHA) injection. Total and IgG antibody titres to SRBC tended to be highest in the WARM hens and these titres were significantly higher than in CONR hens 14 d after challenge.  相似文献   

4.
5.
Intravenous (i.v.) bolus administration of xylazine (XYL) (0.5 mg/kg) immediately followed by a continuous rate infusion (CRI) of 1 mg kg−1 hr−1 for 2, 4, and 6 hr produced immediate sedation, which lasted throughout the duration of the CRI. Heart rate decreased and blood pressure increased significantly (p > .05) in all horses during the first 15 min of infusion, both returned to and then remained at baseline during the duration of the infusion. Compartmental models were used to investigate the pharmacokinetics of XYL administration. Plasma concentration–time curves following bolus and CRI were best described by a one-compartment model. No differences were found between pharmacokinetic estimates of the CRIs for the fractional elimination rate constant (Ke), half-life (t1/2e), volume of distribution (Vd), and clearance (Cl). Median and range were 0.42 (0.15–0.97)/hr, 1.68 (0.87–4.52) hr, 5.85 (2.10–19.34) L/kg, and 28.7 (19.6–39.5) ml min−1 kg−1, respectively. Significant differences were seen for area under the curve ( ) (p < .0002) and maximum concentration (Cmax) (p < .04). This indicates that with increasing duration of infusion, XYL may not accumulate in a clinically relevant way and hence no adjustments are required in a longer XYL CRI to maintain a constant level of sedation and a rapid recovery.  相似文献   
6.
7.
According to current scientific opinion the risk of human infection with H5N1 via preparation and consumption of poultry meat is negligible.This opinion has not yet been challenged by a formal risk assessment, due to the lack of empirical data. We have developed a scenario pathway model as a conceptual framework for a formal assessment of the H5N1 risk to humans through consumption of poultry meat and parameterise the model using information derived from expert opinions. The aim of this study was to investigate whether the notion of an overall negligible risk via the oral infection route is consistent with ad hoc data and expert opinions on the relevant parameters of the model.The model is mainly based on expert opinion. A stochastic Monte-Carlo simulation was conducted which took into consideration (amongst others) the exposure and infection of chicken (broiler and layer), turkeys, ducks and geese, the probabilities of detection prior to slaughter, virus survival and contamination during slaughter, as well as during the cutting and preparation of meat in commercial plants and in private households, respectively. The empirical consumption pattern for poultry meat in Germany was taken into account in the simulation.The results show that the risk for the individual consumer is practically zero whereas up to 23 cases per year in Germany might occur if the upper (more pessimistic) ranges of the expert opinions apply.The finding of a low but non-negligible risk to the population is discussed in relation to the epidemiological information available from recent outbreaks in South East Asia.  相似文献   
8.
Transplantation of ovarian tissue has high potential for female gamete conservation. However, optimal timing of oocyte recovery for in vitro maturation and fertilization is still critical. Therefore the aim of the present study was to use high-resolution transcutaneous ultrasonography to monitor follicular development within xenografted ovarian tissue. Ovarian cortex fragments (n=44) from domestic cats were transplanted into athymic nude rats (n=12). Graft development in the animals was assessed weekly by high frequency ultrasound (10-22 MHz) under two different FSH regimes. Blood collection for serum estradiol determination and vaginal smears were performed simultaneously. The xenografts were removed at different time points according to the ultrasound findings. The survival rate of the transplants 4 weeks after surgery was 54.5% and antral follicular growth was observed within 10 grafts from 5 different hosts (8.6 +/- 6.43 follicles per graft). Early follicle antrums could be detected from 0.4 mm onwards. The growth rate of the antral cavity was calculated from weekly measurements (0.56 +/- 0.44 mm per week). Although vaginal cells and estradiol levels followed a cyclic pattern, no correlation was found between follicular diameter, estradiol and keratinized vaginal cells. We recovered 5, 1 and 4 cumulus oocyte complexes from three different individuals during weeks 19, 21, and 23 respectively. Extrusion of a polar body (1 oocyte) and germinal vesicle break down (7 oocytes) indicated progression of maturation after in vitro culture. We conclude that ultrasonography und provided a reliable method to examine xenograft survival and follicular development within the grafts. Furthermore, this technique is suitable for assessment of the efficiency of hormonal treatment and narrowing of the optimal time frame for oocyte retrieval. To our knowledge, this is the first report of the in vivo development of early antral follicles in mammalian species.  相似文献   
9.
Gegenstand der Untersuchungen sind zwei Dauerfeldversuche, die im Jahr 1984 in Rauischholzhausen (Deutschland) und im Jahr 1996 in Wroc?aw‐Swqjec (Polen) mit vergleichbarer Methode und Zielstellung angelegt wurden. Ausgewertet wurden hier die Zuckerrübenerträge im Mittel der dreijährigen Rotation der Jahre 1997–1999 in Abhängigkeit von organischen und mineralischen Düngungsmaßnahmen. Die erzielten Ergebnisse unterstreichen die Bedeutung der organischen Düngung für die Ertragssicherung im Zuckerrübenanbau. Die untersuchten organischen Dünger Stalldung, Stroh und Biokompost verbesserten die Ertragswirksamkeit mineralischer N‐Gaben.

Die ertragssteigernde Wirkung organischer Dünger war bei fehlender oder niedriger mineralischer N‐Düngung größer als bei hohen N‐Gaben. Auf stark lehmigem Sandboden (Wrozlaw) wurden höhere Ertragseffekte erzielt als auf schwerem Lehmboden (Rauischholzhausen). Die Blatterträge wurden durch die angewendeten Düngungsmaßnahmen stärker beeinflußt als die Rübenerträge. Stroh und Biokompost zeigten die gleichen Ertragseffekte wie Stalldung.  相似文献   
10.
Results of field measurements and laboratory experiments were used to simulate the behaviour of 1,3-dichloropropene (1,3-D) in a loamy sand soil. Microbial activity was described using pre-set conditions to compute transformation rates as dependent on compound concentrations and temperature. These kinetics could only be analysed using non-linear transformation rates. To link the development of microbial populations and the consumption of the compound over time, an iterative technique was used to estimate the necessary parameters.  相似文献   
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