新年祝辞

全国兽医药品行业的全体同仁： 新年好! 在兽药事业发展和改革取得显著成绩的进程中，我们迎来了新的一年。值此辞旧迎新之际，我谨代表中国兽医药品监察所，向全国工作在兽药管理、监察、科研、生产、检验、销售一线的全体同仁致以诚挚的问候和节日的祝福!对所有关心、支持和帮助我们工作的各位领导和朋友们表示衷心的感谢!衷心地祝愿大家在新的一年里，工作顺利，身体健康，阖家幸福，万事如意!     

Expression of 3beta-hydroxysteroid dehydrogenase, cytochrome P450-c17, and sulfotransferase 2B1 proteins in liver and testis of pigs of two breeds: relationship with adipose tissue androstenone concentration

An excessive accumulation of androstenone in pig adipose tissue is a major contributor to the phenomenon of boar taint. Androstenone deposition is dependent on the rate of androstenone biosynthesis in testis and androstenone degradation in liver. The aim of the current study was to examine the possibility of the existence of breed-specific mechanisms controlling androstenone accumulation in pig adipose tissue. The specific objective was to investigate the expression of some of the key enzymes involved in testicular and hepatic androstenone metabolism in pigs of 2 breeds by using animals with high and low androstenone concentrations within each breed. The study was conducted with Norwegian Landrace (N. Landrace) and Duroc boars. The mean androstenone values for the low- and high-androstenone groups were 0.1 +/- 0.01 microg/g and 7.58 +/- 0.68 microg/g for N. Landrace boars, and 0.22 +/- 0.04 microg/g and 13.55 +/- 1.14 microg/g for Duroc boars. The enzymes investigated were 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cytochrome P450-c17, and sulfotransferase 2B1 (SULT2B1). Expression of cytochrome P450-c17 in liver and testis did not differ between animals with high and low androstenone concentrations in either the N. Landrace or Duroc breed. Expression of hepatic 3beta-HSD, which catalyzes the first stage of androstenone degradation, was decreased in high-androstenone N. Landrace boars (P < 0.01), but not in high-androstenone Duroc boars. In contrast, the expression of hepatic SULT2B1, which catalyzes the second stage of steroid catabolism, was decreased in high-androstenone Duroc animals (P < 0.05), but not in high-androstenone N. Landrace animals. Sulfotransferase 2B1 was also inhibited in testis of high-androstenone pigs of both breeds compared with low-androstenone animals. We report breed differences in expression of the androstenone-metabolizing enzymes 3beta-HSD and SULT2B1 in the liver of high- and low-androstenone pigs. It is suggested that accumulation of androstenone in adipose tissue of N. Landrace boars might be related to a low rate of hepatic androstenone degradation in metabolic stage I, whereas the high androstenone concentration in Duroc boars might be related to a low rate of androstenone metabolism in metabolic stage II.     

Food safety and residues in Australian agricultural produce

SUMMARY A brief history of food safety in Australia in the context of the development of scientific knowledge is presented. Australia's food and food commodity residue and contamination surveillance and monitoring programs are outlined. Although chemical residues are perceived as a major health risk by the general community, the risk of food causing illness or death because of chemical residues is low. The major threat to human health from food is microbiological contamination, in terms of deaths, sickness and economic loss. The emerging influences in food safety are scientific and technical developments, deregulation, social and demographic factors, and the media. The risk of disruption of domestic and export markets by food safety issues is considerable. The emergence of international standards for food production and processing will enable commercial contractual arrangements to minimise the frequency of disruptive food safety incidents.     

Statewide Cross-Sectional Survey of Cryptosporidium and Giardia in California Cow-Calf Herds

Cryptosporidium spp. and Giardia duodenalis are common protozoal parasites in livestock including beef cattle on rangeland and irrigated pasture. A statewide cross-sectional study was conducted to determine the prevalence, species or genotype, and risk factors for fecal shedding of Cryptosporidium and Giardia by cattle from California cow-calf operations. Species and genotypes of Cryptosporidium and Giardia were determined by molecular fingerprinting. Prevalence of Cryptosporidium (19.8%) and Giardia (41.7%) in fecal samples from calves were approximately twice as high as fecal samples from cows (9.2% and 23.1%, respectively). In addition to age, multivariable logistic regression showed that higher stocking density and a higher number of replacement heifers were positively associated with fecal shedding of Cryptosporidium while longer calving interval, a winter/spring calving season, and higher numbers of replacement heifers were positively associated with shedding of Giardia. The dominant species and genotypes of Cryptosporidium and Giardia in feces from these cow-calf herds were Cryptosporidium ryanae (75%) and assemblage E for Giardia duodenalis (90%), which have low impact on public health compared with other zoonotic species/genotypes of these two parasites. We identified host and potential management practices that can be used to protect cattle health and reduce the risk of surface water contamination with protozoal parasites from cow-calf operations. In addition, this work updated the scientific data regarding the predominance of low zoonotic genotypes of Cryptosporidium and Giardia shed in the feces of commercial cow-calf herds on California rangeland and irrigated pasture.     

Ileal impaction in the horse: 75 cases

Records of 75 horses with ileal impactions were examined retrospectively. There was a sex predilection towards mares. Arabians were over-represented compared to the hospital population. The average age was 8.3 years. Abdominal pain was observed in 96% of horses. Nasogastric reflux was present in 56% of horses, small intestinal distention was found on rectal palpation in 96% and an ileal impaction in 25%. Exploratory celiotomy was performed in 69 horses, the mass was reduced by extramural massage in 67 horses, and ingesta was removed via enterotomy in 2. Jejunocecostomies were performed in 47 horses. Twenty-five horses developed postoperative ileus, and 11 developed laminitis. Twenty-seven horses survived. Significant differences (p less than 0.05) between survivors and non-survivors were found for rectal temperature (37.7 and 38.2 degrees C, respectively), plasma protein concentration (7.8 and 8.9 g/dl, respectively) and anion gap (15 and 21.3 mEq/l, respectively). Survival decreased with increasing duration of clinical signs. Enterotomy, enterectomy, and/or jejunocecostomy performed during surgery had a deleterious effect on survival.     

Transpalpebral enucleation using a chain écraseur

This study was undertaken to describe the technique, complications and outcome of the use of a chain écraseur for transpalpebral enucleation in horses under general anaesthesia. We report its use in 53 horses, reviewing the subject details, reasons for enucleation, surgical technique, intra‐ and post operative complications, and long‐term outcome. Intraoperative complications included mild to moderate bleeding in 4 horses. Post operative complications included mild periorbital post operative swelling in one horse, transient head tilt in one horse and severe enterocolitis, which resulted in euthanasia in one horse; another 2 horses were subjected to euthanasia after long bone fractures that occurred during recovery from general anaesthesia and 2 horses had the prosthesis removed as a result of inflammatory reaction or infection. Long‐term outcome was available for 38 horses, 25 of which returned to their previous activities and 13 were retired. Twelve horses were lost for follow‐up. Transpalpebral enucleation using a chain écraseur is a feasible alternative to traditional enucleation techniques that can provide adequate haemostasis during transection of the optic pedicle when used properly.     

Stratospheric Mean Ages and Transport Rates from Observations of Carbon Dioxide and Nitrous Oxide

Measurements of stratospheric carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were analyzed to investigate stratospheric transport rates. Temporal variations in tropospheric CO2 were observed to propagate into the stratosphere, showing that tropospheric air enters the lower tropical stratosphere continuously, ascends, and is transported rapidly (in less than 1 month) to both hemispheres. The mean age A of stratospheric air determined from CO2 data is approximately 5 years in the mid-stratosphere. The mean age is mathematically equivalent to a conserved tracer analogous to exhaust from stratospheric aircraft. Comparison of values for A from models and observations indicates that current model simulations likely underestimate pollutant concentrations from proposed stratospheric aircraft by 25 to 100 percent.