Electron microscopic identification and subsequent isolation of a rotavirus from a dog with fatal neonatal diarrhea

Negative contrast electron microscopic examination of intestinal contents from a 3-day-old pup with fatal diarrhea exhibited numerous rotavirus-like particles. Rotavirus was subsequently recovered, using MDCK cells, and was carried through 11 sub-passages; rotavirus-like particles were identified in each passage by negative contrast electron microscopic examination. Experimental inoculation of two 6-month-old Beagle dogs with purified intestinal contents did not result in clinical signs or virus shedding.     

Stability of Perovskite (MgSiO3) in the Earth's Mantle

Available thermodynamic data and seismic models favor perovskite (MgSiO3) as the stable phase in the mantle. MgSiO3 was heated at temperatures from 1900 to 3200 kelvin with a Nd-YAG laser in diamond-anvil cells to study the phase relations at pressures from 45 to 100 gigapascals. The quenched products were studied with synchrotron x-ray radiation. The results show that MgSiO3 broke down to a mixture of MgO (periclase) and SiO2 (stishovite or an unquenchable polymorph) at pressures from 58 to 85 gigapascals. These results imply that perovskite may not be stable in the lower mantle and that it might be necessary to reconsider the compositional and density models of the mantle.     

链霉菌高拷贝质粒pIJ101 DNA的研究 Ⅳ.BclI-E片段上启动子的定位

将链霉菌高拷贝质粒pIJ101上具有明显启动子活性的BclI—E片段(1.18kb)用MboI酶切后克隆到链霉菌启动子探针载体pIJ425中所做的试验证明,当把这个片段的末端去掉以后,中间的两个次级片段(0.63kb和0.68kb)比完整的BclI—E片段具有更强的(4～6倍)激活指标基因neo表达的能力.Southern印迹杂交试验证明这两个片段均来自于pIJ101的BclI—E片段.这项试验不仅大大缩小了BclI—E片段上的启动子活性区域,而且说明BclI—E片段末端有转录终止子的存在.     

Comparison of the sedative effects of medetomidine and xylazine in horses.

The sedative effects in horses of the new alpha 2 agonist medetomidine were compared with those of xylazine. Four ponies and one horse were treated on separate occasions with two doses of medetomidine (5 micrograms/kg bodyweight and 10 micrograms/kg bodyweight) and with one dose of xylazine (1 mg/kg bodyweight) given by intravenous injection. Medetomidine at 10 micrograms/kg was similar to 1 mg/kg xylazine in its sedative effect but produced more severe and more prolonged ataxia, and one animal fell over during the study. Medetomidine at 5 micrograms/kg produced less sedation but a similar degree of ataxia to 1 mg/kg xylazine.     

The lack of effect of parvovirus vaccination on the seminal characteristics of dogs

The onset of ejaculation and development of normal seminal characteristics in six young dogs vaccinated and seroconverting against canine parvovirus did not differ from the accepted range, and by 45 weeks of age the ejaculates were considered to be normal. At one year of age three of the dogs were given a large antigenic stimulus by vaccination once a week for four weeks; this produced no change in the output or characteristics of spermatozoa.     

Reversal of xylazine sedation in dogs.

Intramuscular injections of atipamezole (200 micrograms/kg), doxapram (2.5 mg/kg) and saline (0.1 ml/kg) were compared for their ability to reverse xylazine sedation in dogs. Atipamezole effectively reversed the sedative effects and partially reversed the cardiopulmonary effects of xylazine. Doxapram did not arouse the dogs as much as atipamezole, but it shortened the time taken for them to stand although the dogs were still ataxic.