Several species of insects, exhibiting varying responsiveness to the juvenile hormone antagonist precocene II (6,7-dimethoxy-2,2-dimethylchromene), were challenged topically with a tritiated preparation of the title compound. Metabolism of [3H]precocene II was subsequently examined by withdrawing hemolymph samples from treated animals at appropriate time intervals and characterizing the extractable radiolabel chromatographically. Quantitative (or qualitative) differences observed between the respective metabolic profiles were found not correlative with specimen sensitivity to precocene. Production of two heretofore unreported metabolites, identified by spectral and chemical means as O-β-glucosides of 6- and 7-monodemethylated precocene II, was demonstrated in both sensitive and insensitive species. No evidence for the presence of a hemolymphborne, biologically effective “activated metabolite” produced in vivo by precocene-susceptible insects could be found. The latter finding may well argue for in situ bioactivation of precocene at the target tissue(s) by these sensitive insects. 相似文献
AIM: To assess the benefit of inducing emesis in dogs that have ingested rodenticide bait containing brodifacoum (BDF), by determining the amount of BDF in bait recovered from the vomitus relative to the estimated amount consumed.
METHODS: Between 2014 and 2015 samples of vomitus from seven dogs that ingested rodenticide baits containing BDF were submitted by veterinarians in New Zealand. All seven dogs had been given apomorphine by the veterinarian and vomited within 1 hour of ingesting the bait. Some or all of the bait particles were retrieved from each sample and were analysed for concentrations of BDF using HPLC. Based on estimations of the mass of bait consumed, the concentration of BDF stated on the product label, and the estimated mass of bait in the vomitus of each dog, the amount of BDF in the vomited bait was calculated as a percentage of the amount ingested.
RESULTS: For five dogs an estimation of the mass of bait ingested was provided by the submitting veterinarian. For these dogs the estimated percentage of BDF in the bait retrieved from the vomitus was between 10–77%. All dogs were well after discharge but only one dog returned for further testing. This dog had a normal prothrombin time 3 days after ingestion.
CONCLUSIONS AND CLINICAL RELEVANCE: The induction of emesis within 1 hour of ingestion can be a useful tool in reducing the exposure of dogs to a toxic dose of BDF. The BDF was not fully absorbed within 1 hour of ingestion suggesting that the early induction of emesis can remove bait containing BDF before it can be fully absorbed. 相似文献
The aim of this study was to investigate the effect of dietary supplementation of nanosize zinc on zinc digestibility, growth performances, immune response and serum parameters of weanling piglets. Ninety‐six LYD weanling piglets were assigned to control, zinc oxide (ZnO), organic‐Zn (Zn‐methionine) and nanosize ZnO (nano‐Zn) groups with four replicates. The zinc was at the 120 mg/kg level in the treatment group's diet, while the control group's was 80 mg/kg Zn. The experiment results indicated that the nano‐Zn and organic‐Zn groups had significantly higher Zn digestibility compared to the ZnO and control groups. For the immune response traits, the IgG level and goat red blood cells (GRBC) antibody titer were nano‐Zn and organic‐Zn>ZnO>control; in the phytohemagglutinin (PHA) challenge test result, nano‐Zn>organic‐Zn>ZnO>control; in regard to the γ‐globulin level, nano‐Zn and organic‐Zn>ZnO and control, with significant difference between groups. In the serum parameters aspect, serum Zn concentration in nano‐Zn and organic‐Zn groups were higher than in the ZnO and control groups, serum growth hormone concentration was increased in the nano‐Zn group than in the other groups. In conclusion, nanosize zinc oxide for dietary supplementation can increase zinc digestibility, serum growth hormone levels and carbonic anhydrase activity and enhance the immune response of weanling piglets. 相似文献
The characteristics of recovery from total intravenous anesthesia (TIVA) with propofol and inhalation anesthesia with isoflurane was clinically compared in 149 client-owned dogs that anesthetized for surgical or diagnostic procedures. In all dogs, anesthesia was induced with an intravenous injection of propofol following premedication with acepromazine or diazepam. As a result, 58 dogs anesthetized with propofol-TIVA showed slower but smoother recovery than 91 dogs anesthetized with isoflurane anesthesia. The dogs stood at 34.5 +/- 19.3 and 27.7 +/- 17.2 min after propofol-TIVA and isoflurane anesthesia, respectively. Adverse effects, including hypersalivation, neurologic excitement (paddling, muscle tremor/twitching, opisthotonos) and vomiting/retching, were observed in similar infrequent incidences during the recovery from both anesthetic protocols. Propofol-TIVA is suggested to be an alternative anesthetic protocol for canine practice. 相似文献
Biosynthesis of juvenile hormone in the tobacco hornworm, Manduca sexta, is inhibited by the bisthiolcarbamate juvenoid N-ethyl-1,2-bis(isobutylthiolcarbamoyl)ethane both in vitro and in vivo. In vitro an extremely steep dose-response curve was obtained with an ID50 value of 6 × 10?6M. However, in vivo topical treatment with the compound resulted in mild JH antagonistic symptoms, suggesting rapid metabolism of the compound. In agreement with results from metabolic studies performed on plants and in mammals, sulfoxidation of the thiocarbamate S-(4-chlorobenzyl)N,N-diethylthiocarbamate resulted in an enhanced inhibitory effect on JH biosynthesis in vitro. This suggests that the corresponding thiocarbamate sulfoxides may act as intermediates in carbomylating critical thiol sites important in the terpenoid biosynthesis pathway. Furthermore, this study shows that these prototype compounds are interesting tools for further investigation of chemical inhibition of JH biosynthesis in insects. 相似文献
1. In order to promote the establishment of the first marine protected area (MPA) in Taiwan, the conservation values of 12 reef sites in the Penghu Islands were evaluated. The results together with a 6‐year surveillance programme revealed that the Chinwan Inner Bay (CIB) possesses the best coral community in the Penghu Islands with the highest coral cover, high species diversity and habitat types, as well as a high conservation value.
2. Utilization of biological resources and socio‐economic factors of CIB were investigated by intensive field surveys and a complete visit‐and‐poll survey respectively. Most of the fishing at CIB is for recreational purposes and is characterized by low investment, low harvest rates, high dependence on weather conditions, and self‐consumption.
3. The socio‐economic data showed that there was basically no direct conflict of interests with local communities at two neighbouring villages, and most local residents indicated that they would support the MPA proposal.
4. A blueprint for a CIB MPA based on the results of these biological and socio‐economic investigations is proposed. Environmental threats including anchor damage and the predation of Drupella snails need to be ameliorated and monitored through the implementation of appropriate management. The involvement of local communities is key to the success of this MPA and environmental education is recommended to promote public awareness.
Garlic organosulfur compounds are recognized as potential chemopreventive compounds. This protection is related to the induction of phase II detoxification enzymes. We previously reported that diallyl disulfide (DADS) and diallyl trisulfide (DATS) up-regulate the gene expression of the pi class of glutathione S-transferase (GSTP) and that an enhancer element named GPE I is required for this induction. In the present study, we further investigated the signal pathway involved in DADS and DATS up-regulation of this detoxification enzyme in Clone 9 cells. Cells were cultured with 25-200 micromol/L of DADS or DATS for 24 h. Western and Northern blots showed that both garlic allyl sulfides concentration dependently induced GSTP protein and mRNA expression, respectively. Changes in GST activity toward ethacrynic acid were consistent with the increase in GSTP expression (P < 0.05). Electromobility gel shift assay showed that the DNA binding activity of nuclear activator protein-1 (AP-1) is concentration-dependently increased in the presence of DADS and DATS as compared with that of the control cells. The phosphorylation of c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), but not of p38, was stimulated in the presence of both garlic allyl sulfides. Pretreatment with SP600125 and PD98059, which are JNK and ERK inhibitors, respectively, abolished the increase in AP-1-DNA binding activity and also the induction of GSTP protein by either allyl sulfide. Our results indicate that the effectiveness of DADS and DATS on GSTP expression is likely related to the JNK-AP-1 and ERK-AP-1 signaling pathways and, thus, that DADS and DATS enhance the binding of AP-1 to GPE I. 相似文献