Influence of diet on basal and growth hormone-stimulated plasma concentrations of IGF-I in beef cattle

The effects of nutrition on plasma concentrations of insulin-like growth factor-I (IGF-I) were characterized in steers under basal conditions and following single i.m. injection of bovine growth hormone (bGH, .1 mg/kg BW). Nutritional effects on IGF-I were studied in three trials. In all trials steers were individually fed and penned Angus or Hereford x Angus (280 kg). In the first trial, two diets (LPLE1: 8% CP and 1.96 Mcal ME/kg, 4.5 kg.hd-1.d-1; MPHE1: 11% CP, 2.67 Mcal ME/kg, 6.5 kg.hd-1.d-1) were fed (n = 5/diet). Plasma IGF-I concentrations averaged 74 (LPLE1) and 152 (MPHE1) ng/ml (P less than .02). Following bGH injection, IGF-I increased to peak concentrations between 12 and 24 h (averaging 105 and 208 ng/ml at peak for LPLE and MPLE, respectively, P less than .01). In the second trial, steers were fed diets composed of 8, 11 or 14% CP and 1.96 or 2.67 Mcal ME/kg dry matter (6.35 kg.hd-1.d-1 in a factorial arrangement for 84 d, n = 4/diet). Within the low ME diet groups, plasma IGF-I was similar in steers fed 11 and 14% CP but greater at these two CP levels than in steers fed 8% CP (P less than .05). Within the high ME diet groups, plasma IGF-I increased linearly with CP (P less than .01). In the third trial, steers were fed diets to result in a negative N status. Insulin-like growth factor-I was lower (P less than .02) during feed restriction than when steers were full-fed. The IGF-I response to bGH was diminished or absent in underfed steers (P less than .01). These data are interpreted to suggest that diet composition and intake affect plasma concentrations of IGF-I in steers. In cattle, CP may be the primary nutritional determinant of basal IGF-I, but the IGF-I response to CP may be affected by the available ME. Undernutrition can attenuate the IGF-I response to GH and uncouple the regulation of IGF-I normally ascribed to GH.     

Prediction of empty body components in steers by urea dilution

Empty body composition of 68 mixed-breed and 50 Angus steers was determined by chemical analysis of the right half-carcass and entire noncarcass fraction of each steer. Chemical composition was used to develop prediction equations for empty body protein (EBPRO) and fat (EBFAT) in steers using urea space (US) and body weight measurements. Previous research showed a significant positive correlation between empty body water (EBH2O) and urea space in these steers. For all steers studied, the percentage of EBH2O ranged from 44.8 to 69.2 (mean = 56.0), the percentage of EBPRO ranged from 14.1 to 19.8 (mean = 17.0) and the percentage of EBFAT ranged from 6.1 to 38.1 (mean = 22.1). The best predictions obtained were multiple regression equations with actual weight of body components as dependent variables and US and empty body weight (EB) as independent variables. Urea space alone was a poor predictor of EBFAT, but US improved predictions based on live weight (LW) or EB alone. Coefficients of determination for the best predictions of percentage of composition were not as high as coefficients of determination for the best predictions of actual weight of body components. These data suggest that US measurements can be used to predict empty body composition of live steers, but this may require repeated measurements and an independent estimate of EB from LW for greatest accuracy.     

Osmotic stress in red blood cells from beagles with hemolytic anemia.

Red blood cell populations separated by density centrifugation were compared in a dynamic assay of osmotic stress. Red blood cells from Beagles genotypically normal and nonanemic (nonaffected), Beagles with inherited hemolytic anemia (anemic), and Beagles presumed to be carriers of the anemia trait (trait carriers) were examined for rate and extent of swelling after exposure to the ionophore A23187 in a medium containing calcium and potassium chloride. Comparisons were made between RBC populations separated on the basis of density. Significant differences were observed in the rates of cell swelling in RBC populations separated by density between nonaffected and anemic Beagles. The response of RBC from Beagles presumed to carry the anemia trait was similar to that of RBC from nonaffected dogs. One phenotypic expression of this inherited abnormality of RBC in Beagles was an accelerated rate of RBC swelling under osmotic stress, and this swelling response diminished with increasing RBC density.     

Assessment of low-cost teleradiology for grading elbow dysplasia.

Teleradiology involves the creation of a radiographic image that is then transmitted electronically. It has been shown that low-cost teleradiology has a high level of agreement when comparing the original radiograph to the digital image. However, there has been little investigation of the effect of digitization on the score allocated by a grading scheme. Radiographs of 60 canine elbows were selected, each in three projections (mediolateral flexed, mediolateral neutral, craniocaudal). Each radiograph was photographed at 3 megapixel (3 M) and 6 megapixel (6 M) resolution using a digital camera. The images were placed in groups (radiographs, 3 M and 6 M) and randomized. Each elbow was independently graded by a radiologist and an orthopedic surgeon using the BVA elbow scoring scheme, with the different image sets interpreted separately. Intra and interobserver agreement was compared using a kappa analysis. The radiologist had substantial intraobserver agreement for repeated grading of radiographs, and moderate agreement for the other intraobserver tests (3 M vs. radiographs, 6 M vs. radiographs, 3 vs. 6 M). The surgeon had moderate to substantial agreement for the intraobserver tests. There was reduced interobserver agreement for all image groups. These results suggest that low-cost teleradiology may only allow moderate accuracy when used for grading schemes, and this may affect its use for breed scoring schemes. However, there appears to be an inherent subjectivity present in the elbow-grading scheme, seen in both intra and interobserver analysis. Therefore, further study of teleradiology using a different scoring model (e.g., hip dysplasia) may be indicated.     

梨韧皮部特异表达启动子AtSUC2驱动下的GUS基因的转化和表达

 以 ‘Old Home’ 梨无菌苗叶片为外植体, 利用根癌农杆菌介导将专一在韧皮部表达启动子AtSUC2 驱动下的GUS 基因转入 ‘Old Home’中。筛选出了‘Old Home’ 梨叶片高效遗传转化的最佳条件：农杆菌和外植体在液体培养基上共培比在固体培养基上共培转化率提高5倍。 PCR分析和Southern 杂交鉴定表明GUS 基因已整合到转基因植株的基因组中,组织化学检测和Western 杂交鉴定证明了GUS 基因在转基因植株韧皮部中的表达。     

IMAGING DIAGNOSIS—MAGNETIC RESONANCE IMAGING OF DIFFUSE LEPTOMENINGEAL OLIGODENDROGLIOMATOSIS IN A DOG WITH “DURAL TAIL SIGN”

A case of diffuse leptomeningeal oligodendrogliomatosis affecting the brain and spinal cord of a dog is presented. A 7.5‐year old, male neutered Staffordshire bull terrier presented for evaluation of a chronic history of tetraparesis and seizures, with a multifocal neuroanatomical localization was determined. Extra‐axial intradural lesions with an atypical presentation of a dural tail sign were seen on MRI. Histologically, the lesions were consistent with leptomeningeal oligodendrogliomatosis. To the authors’ knowledge, a dural tail sign has not previously been reported as an MRI characteristic of diffuse leptomeningeal oligodendrogliomatosis in dogs.