Heterozygote detection for maple syrup urine disease in cattle

SUMMARY The clinical, pathological and biochemical manifestations of maple syrup urine disease (MSUD) are similar in Poll Hereford and Poll Shorthorn X Poll Hereford calves. No significant differences were observed in branched-chain amino acid concentrations in plasma, or of branched-chain keto acid dehydrogenase activity in fibroblasts, between Poll Herefords homozygous normal and heterozygous for the mutation responsible for MSUD. Haemopoietic chimerism resulted in incorrect diagnosis of the MSUD genotype in 30% of non-identical twins when blood DNA was analysed using allele-specific amplification. Hair roots are shown to be a suitable source of target DNA for genotyping Poll Hereford cattle for the MSUD mutation. Twelve of 203 (5.8%) aged Poll Hereford bulls, sampled at saleyards during the last 4 months of 1993, were found to be heterozygous for the mutation. In contrast, the mutant sequence was detected in only 1 of 150 (0.7%) 2- and 3-year-old Poll Hereford bulls offered for sale at 2 stud sales held during 1993, suggesting that the prevalence of the disease may decline over the next few years.     

Progressive ethmoidal haematoma in horses

Progressive ethmoidal haematoma was diagnosed in 12 Thoroughbreds, 1 part- Arab and 1 stock horse. Ages ranged from 3 to 18 years and both males and females were affected. Diagnosis was based on history, clinical signs, endoscopic and radiographic findings, and was confirmed histologically in 10 cases. Eleven (78%) of the lesions were unilateral and 3 (22%) were bilateral. Two horses were euthanased on diagnosis, 4 were treated conservatively. Of the latter, 3 were euthanased 6 to 24 months after diagnosis, due to progression of the lesions, while 1 case resolved completely within 13 months. Eight horses were treated by surgical excision of the lesion. Three died in the post-operative period, 3 were euthanased within 48 months after recurrence of the condition, and 2 had no recurrence within 60 and 72 months, respectively.     

The Seismic Structure of the Sun

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.     

Off-axis crustal thickness across and along the east pacific rise within the MELT area

Wide-angle seismic data along the Mantle Electromagnetic and Tomography (MELT) arrays show that the thickness of 0.5- to 1. 5-million-year-old crust of the Nazca Plate is not resolvably different from that of the Pacific Plate, despite an asymmetry in depth and gravity across this portion of the East Pacific Rise. Crustal thickness on similarly aged crust on the Nazca plate near a magmatically robust part of the East Pacific Rise at 17 degrees15'S is slightly thinner (5.1 to 5.7 kilometers) than at the 15 degrees55'S overlapping spreading center (5.8 to 6.3 kilometers). This small north-south off-axis crustal thickness difference may reflect along-axis temporal variations in magma supply, whereas the across-axis asymmetry in depth and gravity must be caused by density variations in the underlying mantle.     

Benign masses in the pericardium of two dogs

Two miniature Schnauzer dogs were treated for pericardial masses. In one dog the mass consisted of necrotic fat that was attached to the apex of the pericardium by a pedicle. No obvious communication with the abdomen was present. The second dog had a peritoneopericardial hernia associated with a chronic cystic haematoma. In each case the mass was presumed to have arisen following congenital displacement of the omentum into the pericardium. The pericardial mass was removed and subtotal pericardectomy performed in both dogs. Recovery was complete in each case.     

不同利用方式下草地土壤微生物及土壤呼吸特性

通过对呼伦贝尔羊草(Leymus chinensis)草甸草原土壤呼吸特性及土壤微生物的测定,研究了3种不同利用方式(围封、放牧和刈割)对天然草地土壤呼吸特性及土壤微生物的影响,为草甸草原土壤呼吸研究提供基础理论依据。结果表明:不同利用方式下土壤呼吸速率、土壤微生物量碳含量与土壤酶活性(除脲酶)均表现为草地围封比放牧和刈割呼吸速率高(含量高、活性强);土壤微生物量氮含量、脲酶活性和微生物数量表现为草地放牧和刈割比围封的含量高(活性强、数量多);土壤微生物量碳、氮含量、土壤酶活性(除脲酶)和土壤微生物数量均以表层(0～10cm)最高(活性最强、数量最多),随着土层深度增加而降低(活性下降、数量减少)。土壤呼吸速率与微生物量碳、土壤酶活性(除过氧化氢酶)成正相关,与微生物量氮、过氧化氢酶和微生物数量成负相关,其中只与微生物量氮相关性显著,而其余之间均不显著。     

Comparison of the Level(s) of DNA Damage Using Comet Assay in Bovine Oocytes Subjected to Selected Vitrification Methods

It was suggested that the cryodamage to oocytes' DNA has been responsible for the compromised developmental competence of cryopreserved oocytes. Vitrification of bovine oocytes affected not only cellular components, but also nuclear material. A significant rate of DNA fragmentation was found in bovine frozen or vitrified oocytes analysed by Comet assay regardless of cryopreservation method. Our method of vitrification using droplet system after gentle pre-equilibration treatment is one of the most effective cryopreservation methods employed for bovine oocytes so far, making it possible to develop 30% blastocyst stage embryos. In this study, the extent of DNA damage in bovine oocytes vitrified using three vitrification methods (droplet system, Open Pulled Straw and traditional vitrification in 0.25 ml insemination straws) was compared using Comet assay. Vitrification in droplet system and Open Pull Straws vitrification did not result in detectable cryoinjuries of DNA of bovine oocytes. On the contrary, DNA fragmentation was found in four of 26 oocytes vitrified in 0.25 ml straws (15.4%, p   ≤ 0.05 in comparison with the other vitrification methods).