Effects of age on the electroencephalographic response to castration in lambs anaesthetised using halothane in oxygen

AIM: To use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex to the noxious stimulus of castration varied with age in lambs.

METHODS: Two groups of East Friesian lambs were selected according to age; the mean age of the younger group (n=21) was 12 (SD 2) days and the older group (n=20) was 29 (SD 1) days. Anaesthesia was induced via mask using 4% halothane in oxygen, and maintained using 1.5% halothane in oxygen at a flow rate of 4 L/min. Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiographic (ECG) readings commenced, and the lambs were castrated 15 min later, using rubber rings. Median and 95% spectral edge frequencies (F95) and total EEG power (ptot) were derived from data from the EEG.

RESULTS: Following castration, there was an increase in the median frequency (F50) in the younger lambs (p=0.002), and an increase in ptot in both groups (p=0.05), which was of greater magnitude in the older lambs. There were no significant changes in the F95. Both younger and older lambs exhibited a transient bradycardia (p=0.001 and p=0.01, respectively).

CONCLUSIONS: These differences in the cortical response between the two groups suggest that 2-week-old lambs undergo a qualitatively different perception of the noxious stimulus of castration compared to 4-week-old lambs.     

A Magnetic Signature at Io: Initial Report from the Galileo Magnetometer

During the inbound pass of the Galileo spacecraft, the magnetometer acquired 1 minute averaged measurements of the magnetic field along the trajectory as the spacecraft flew by Io. A field decrease, of nearly 40 percent of the background jovian field at closest approach to Io, was recorded. Plasma sources alone appear incapable of generating perturbations as large as those observed and an induced source for the observed moment implies an amount of free iron in the mantle much greater than expected. On the other hand, an intrinsic magnetic field of amplitude consistent with dynamo action at Io would explain the observations. It seems plausible that Io, like Earth and Mercury, is a magnetized solid planet.     

Regulation of Luteal Function and Corpus Luteum Regression in Cows: Hormonal Control, Immune Mechanisms and Intercellular Communication

The main function of the corpus luteum (CL) is production of progesterone (P4). Adequate luteal function to secrete P4 is crucial for determining the physiological duration of the oestrous cycle and for achieving a successful pregnancy. The bovine CL grows very fast and regresses within a few days at luteolysis. Mechanisms controlling development and secretory function of the bovine CL may involve many factors that are produced both within and outside the CL. Some of these regulators seem to be prostaglandins (PGs), oxytocin, growth and adrenergic factors. Moreover, there is evidence that P4 acts within the CL as an autocrine or paracrine regulator. Each of these factors may act on the CL independently or may modify the actions of others. Although uterine PGF_2α is known to be a principal luteolytic factor, its direct action on the CL is mediated by local factors: cytokines, endothelin-1, nitric oxide. The changes in ovarian blood flow have also been suggested to have some role in regulation of CL development, maintenance and regression.     

Tibial tuberosity advancement in 92 canine stifles: initial results,clinical outcome and owner evaluation

Objective To investigate the clinical outcomes, complications and owners' evaluation of the tibial tuberosity advancement (TTA) procedure in canine stifles. Methods A retrospective study of hospital records was performed to identify dogs diagnosed with partial or complete cranial cruciate ligament (CCL) rupture that had undergone TTA repair. Information obtained included signalment, period of lameness, surgical report, evidence of meniscal injury, postoperative recovery and peri-operative complications. Owners were asked to assess the long-term outcome. Results In a total of 72 dogs (median age, 6 years; median body weight, 34.8 kg), TTA was performed in 92 stifles. Twenty breeds were represented, with Labrador Retrievers and Rottweilers the most common. The period of lameness ranged from 3 days to 24 months. The median pre-operative lameness score was 3/4 and meniscal injury was present in 51 stifles. Minor complications occurred in 29% of cases. Major complications occurred in 6.5% of cases and consisted of meniscal injury and two tibial tuberosity fractures. All were successfully managed, with good limb function when subsequently assessed. In the owner evaluation, 96% reported moderate to great improvement postoperatively, with no lameness at rest and mild to no lameness after vigorous exercise. Conclusion Clinical outcome and owner evaluations in this case series indicate favourable results can be expected when CCL-deficient stifles are treated with TTA.     

在西双版纳地区进行玉米南繁加代的可行性研究

我单位在云南西双版纳地区连续３年进行玉米南繁试验,事实证明,１０月１０日前播种是阳适宜播期,于１２月授粉,２月上中旬收获,生长期间未遇低温危害;１１月１５日前播种,采用地膜覆盖栽培,于１２月至１月授粉,在花期遇７￣８℃低温的情况下,开花授粉及结实仍然良好,一般完成授粉任务的９５％以上。３月中下旬收获,４月中子可运回,及时为春播提供种源。在西双版纳有大量的冬闲土地,并且气候温和,从不受台风影响,南繁