TECHNICAL PARAMETERS AFFECTING IMAGE CHARACTERISTICS IN IN VIVO MR MICROSCOPY OF THE MOUSE

The aim of the study was to assess the effects of changing acquisition parameters used for high-resolution in vivo magnetic resonance (MR) microscopy on image quality and scan time. The head or abdomen of 11 normal and 1 glioblastoma-bearing anesthetized BALB/c mice were imaged using a high-resolution 7.0-Tesla magnet. Scan parameters such as matrix size (MTX), slice thickness (ST), number of excitations (NEX), pulse sequence type including repetition time (TR) and echo time (TE), respiratory gating, and intraperitoneal contrast medium administration were altered to assess their actual effect on signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) as compared to calculated effects. As expected, SNR increased with increasing ST or NEX and with decreasing MTX. However, although the empirical increase in SNR was similar to that expected for increased ST, it was less than that anticipated for increasing NEX or decreasing MTX. Increasing NEX and applying respiratory gating both increased SNR and reduced the image degradation associated with respiratory motion in images of the abdomen. Intraperitoneal contrast medium administration produced a marked increase in CNR in the subject with the implanted glioblastoma, suggesting that this route is satisfactory for the enhancement of lesions disrupting the blood-brain barrier. The consequence of improving image quality in terms of spatial and contrast resolution is increased scan time. However, the actual increase in SNR when altering acquisition parameters may not be as much as predicted by theory.     

THE COMPUTED TOMOGRAPHIC ENHANCEMENT PATTERN OF THE NORMAL CANINE PITUITARY GLAND

Dynamic computed tomography (CT) of the pituitary gland was performed on four healthy male dogs of similar size, weight and age. The pituitary gland region was first identified on lateral scout and transverse non-contrast images. After localization, water soluble iodinated contrast medium was administered intravenously as a bolus at a dose of 1 ml/lb using a pressure injector at an injection rate of 10 ml/sec and a total of 40 post contrast images of the pitutary gland were acquired. No images were made after 400 seconds. The same pituitary region was imaged in each slice. The slice thickness was 1.5 mm, with a two second scan time and an eight second delay between images (resulting in images every ten seconds). The contrast medium injection and initial image were acquired simultaneously, resulting in a non-contrast enhanced initial image. At the completion of the CT scan, a region of interest (ROI) was drawn around the pituitary gland and time density data were obtained. The mean pituitary Hounsfield number was plotted as a function of time. A bi-exponential least squares model was used to derive the best fitting line through the data. The mean relative peak increase in pituitary Hounsfield Units (HU) was 65.9% +/- 2.1%. After the initial increase there was a decrease in pituitary Hounsfield number with a half-time of 16.1 seconds, followed by a slower phase with a half-time of 16.5 minutes. The mean pituitary gland HU value during the period of gradual opacity decline was 35.0% +/- 4.4% above that of the pre-contrast image. Establishing the enhancement pattern in the canine pituitary gland is the precursor to the clinical application of dynamic CT of the pituitary gland to diagnose pituitary microadenomas and/or small macroadenomas before they become exceptionally large.     

ST segment depression and ventricular fibrillation in a dog after contrast agent administration

An 11-year-old Toy Poodle underwent a computed tomography examination with contrast (iohexol) enhancement under anesthesia. Heart rate and R-wave amplitude on electrocardiogram (ECG) increased 2.5 min after iohexol administration, and end-tidal carbon dioxide decreased to 12 mmHg. A progressive ST segment depression was observed on ECG. Subsequently, the ECG waveform changed to ventricular fibrillation. However, spontaneous circulation returned following cardiopulmonary resuscitation. Myocardial ischemia or anaphylactic shock was suspected in the dog, which explains the ST segment depression observed on ECG. When performing radiological examinations with a contrast agent, the ECG waveform changes, such as an increase in heart rate, R-wave amplitude, or ST segment depression, should be carefully monitored. This might enable early detection of cardiac dysfunction and the ensuing cardiac arrest in dogs.     

INTRAARTERIAL CONTRAST-ENHANCED COMPUTED TOMOGRAPHY OF THE EQUINE DISTAL EXTREMITY

A technique for regional delivery of contrast medium to the foot of the horse to increase the diagnostic utility of computed tomography (CT) for the characterization of soft tissue structures within the hoof capsule was developed. An intraarterial catheter was placed under ultrasound guidance into the medial palmar artery at the level of the carpus to facilitate a steady-state infusion of iodinated contrast medium. Two 5 mm collimated contiguous acquisition CT scans were performed in 10 horses without lameness or radiographic evidence of distal sesamoid bone degeneration. CT examination was performed before and during regional arterial infusion of iodinated contrast medium administered at a rate of 2 ml/s. Cross-sectional area and mean pre- and post-contrast attenuation of the deep digital flexor tendon and the collateral ligaments of the distal interphalangeal joint were quantified from CT images. Soft tissue anatomy of the foot was also qualitatively characterized from pre- and postcontrast images. Catheterization was successful and without complication in all horses. The evaluated tendons and ligaments were clearly visible and had a small (8-20 Hounsfield Unit) but significant (P < 0.05, paired t-test) increase in attenuation during the steady-state infusion of contrast medium. This study should enhance the diagnostic potential of CT by providing baseline quantitative data for comparison with horses affected with soft tissue injuries in the distal extremity causing lameness that is alleviated with a palmar digital nerve block.     

微量元素添加剂对奶牛泌乳性能影响

针对奶牛日粮营养不平衡,导致产奶量低、乳脂率低,经济效益低的生产状况,本试验随机选择4胎、5胎、6胎泌乳期牛10头,分试验组与对照组,各试验牛按日产奶量饲喂不等量精料补充料、玉米秸与稻秸按2:1混合的粗饲料、尿素基础饲粮。试验组饲粮按产奶量分等添加微量元素添加剂,试验期试验组奶料比为3.25,对照组为2.9,试验组增加0.34kg(P<0.05)。试验期产奶量按4.0%标准乳计算,试验组日产奶量高于对照组4.31kg(P<0.05)。按每kg增重折合鲜奶8.0kg校正体重后标准乳计算,试验组日产奶量高于对组4.36kg(P<0.01)。乳脂、乳钙、乳蛋白质(2.29 乳脂率×0.33计算),试验组比对照组分别提高0.32%、0.10%、0.03%(P<0.05)。添加微量元素的试验组,头均日产标准奶24.12kg,对照组19.8kg(P<0.05),按kg鲜奶1.80元计算,头、日产奶分别收入43.42元、35.62元(P<0.05)。头均日耗饲料的实际价格试验组9.15元、对照组7.82元(P<0.01),试验组比对组多增收6.46元(P<0.05),经济效益显著。     

Contrast echocardiography in Boxer dogs with and without aortic stenosis

ObjectivesThe aim of this study was to investigate whether contrast echocardiography could enhance the subcostal Doppler signal for aortic flow measurements and achieve myocardial opacification, in Boxer dogs with and without AS.BackgroundIn evaluating dogs for aortic stenosis (AS) subcostal Doppler echocardiography was used for measurement of the aortic flow velocity, a measurement that can sometimes be difficult to perform in Boxer dogs.Animals, materials, and methodsCardiac auscultation, phonocardiographic and echocardiographic examinations, including a contrast study with Optison, were performed on 29 Boxer dogs selected based on previous examinations.ResultsThe initial subcostal Doppler signal was weak in 66% of the dogs and a marked improvement was seen in all dogs after contrast injection. The peak aortic flow velocity increased 5% from 2.58 ± 1.42 m/s before contrast to 2.71 ± 1.54 m/s after contrast (p = 0.003). This corresponds to a 2.8 mmHg increase in the pressure gradient from 26.6 mmHg before to 29.4 mmHg after contrast. A dose of 0.05–0.1 mL of Optison administered intravenously resulted in approximately 4 min of Doppler signal enhancement. With the present technique contrast echocardiography did not achieve myocardial opacification.ConclusionsSingle use of the contrast agent Optison can be recommended for enhancement of the subcostal Doppler signal in dogs, in which plain Doppler signals are difficult to obtain. Albeit statistically significant, the mild increase in peak aortic flow velocity after contrast was not considered biologically or clinically significant.     

Iohexol myelography in the horse

Iohexol, a water soluble non-ionic contrast agent, was evaluated for myelography in the horse. Both 300 and 350 mg iodine/ml iohexol gave diagnostic cervical myelograms. Pathological changes were limited to extradural oedema and an increase in the number of white blood cells and specific gravity in the cerebrospinal fluid two days after myelography. This increase in white blood cells in the cerebrospinal fluid was, however, much less than that recorded by other authors using metrizamide and iopamidol contrast media. These findings indicate that iohexol is a less irritant myelographic contrast agent than those previously evaluated in the horse.     

DIFFERENTIATION OF NEOPLASTIC FROM NON-NEOPLASTIC LESIONS IN DOG BRAIN USING QUANTITATIVE CT

The uptake and washout of iodinated contrast medium in neoplastic and non-neoplastic lesions in the dog brin was quantified using computed tomography. The magnitude of tissue contrast enhancement was measured during and up to 15 minutes following an intravenous infusion of contrast medium. Compartmental analysis was used to obtain rate contants for contrast medium movement into and out of brain lesions. In non-glioma tumors, contrast enhancement was maximum during the infusion and the rate of contrast washout was comparable to that measured in the normal brain. Mixed gliomas also showed maximum enhancement during infusion, but there was no washout of contrast. Contrast enhancement in radiation-induced brain damage and cystic encephalomalacia secondary to tumor compression continued to increase for 5–15 minutes after infusion; rate constants in these non-tumor lesions were different from all tumors studied. Hyperthermia-induced lesions had comparable rate constants for contrast washin and washout. These results indicate that kinetic CT studies provide a non-invasive measure of permeability differences between lesions, may be useful in differentiating certain types of intracranial lesions, and may provide an effective method for patient follow-up after treatment.     

普通青贮玉米与微生物青贮玉米对奶牛产奶量的对比试验

研究普通青贮玉米和微生物青贮玉米对奶牛产奶量的影响.选取20头生理情况基本一致黑白花奶牛,分为试验组和对照组进行交叉对比试验.结果显示：饲喂微生物青贮玉米的奶牛,产奶量比饲喂普通青贮玉米的高2.27 kg,每天纯收入多7.93元.     

Antibody reactivity to Cryptosporidium parvum in saliva of calves after experimental infection

Antibodies against Cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. Salivary anti-C. parvum IgA antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. Salivary anti-C. parvum IgG antibody levels showed a gradual increase along with the change in IgA antibody levels during the infection. In contrast, serum anti-C. parvum IgA antibody levels showed only a slight increase between days 15 and 30 post-challenge. Serum anti-C. parvum IgG antibody levels rose on day 12 post-challenge and one calf maintained relatively high level up to the end of the experiment. In immunoblotting, an antigen with a molecular mass of 15 kDa was found to react strongly to salivary IgA antibody and a 27 kDa antigen to react to serum IgG antibody.     

Exocrine pancreas secretion in swine after feeding soybean extract meal

Exogenous N-secretion of the pancreas was investigated with growing pigs with fistulae in the pancreas. For this purpose the two protein sources toasted and untoasted soybean oilmeal were used. After the feeding of untoasted soybean oilmeal a significant increase of the secretion volume and of protein outpour could be observed in contrast to toasted soybean oilmeal within 24 h. The heat-labile soybean trypsin inhibitor also caused an activity increase of the pancreatic enzymes.     

Alterations in piglet small intestinal structure at weaning

The small intestinal mucosa of 112 piglets aged between 21 and 32 days was examined to identify the effects on its structure of weaning and of consumption of creep food. In unweaned control pigs a gradual increase in crypt depth occurred with age, while villus height altered little. In contrast, weaned pigs showed a highly significant increase in crypt depth and an increase in the complexity of villus morphology with a dramatic reduction in villus height. Crypts elongated most in the distal small intestine, while the loss of villus height was greatest proximally. No inflammatory reaction was seen and the alterations were not influenced by consumption of creep food before weaning. This failed to support the hypothesis that hypersensitivity to dietary antigens is involved in the aetiology of such intestinal changes. The reduction in small intestinal absorptive area and the appearance of a less mature enterocyte population help to explain the increased susceptibility of the pig to diarrhoea and growth checks in the post-weaning period.     

金银花在肉鸡饲料中的应用效果研究

采用对比试验,将60只7日龄哈巴特肉鸡随机分为2组（对照组和试验组）,每组10个重复,每个重复3只,饲养在不锈铜笼中。对照组和试验组分别饲基础喂日粮、添加0．3％金银花基础日粮,结果表明,试验期间试验组与对照组鸡的日采食量、日增重、饲料转化率、周末体重差异不显著（P〉0．05）。添加0．3％金银花在7—21日龄与21-42日龄时,肉鸡的日增重分别比对照组提高3．98％和1．33％;胸腺、法氏囊、脾脏脏器指数分别比对照组提高6．94％、4．93％、2．86％,差异不显著（P〉0．05）.     

Histomorphological changes in the oviduct epithelium of the rabbit during early pregnancy

In this study, we determined the histomorphological changes in different regions of the oviduct (fimbriae, infundibulum, ampullae and isthmus) during early pregnancy (days 1-4) of the rabbit. It was observed that the number of secretory cells (PAS-positive cells) diminished in the fimbriae during the first 4 days of pregnancy with the corresponding increase in the number of non-secretory cells (PAS-negative cells). In contrast, there was an increase in the number of PAS-positive cells in the isthmus during early pregnancy. In both the infundibulum and the ampullae the number of PAS-positive cells was increased on day 3. A significant decrease in the height of the epithelium was observed in the fimbriae during early pregnancy. On the contrary, a significant increase in this parameter was observed in the isthmus during the first 3 days of pregnancy. A slight decrease in the height of the epithelium was observed in the infundibulum on day 4 of pregnancy, while in the ampullae it was significantly increased on days 1 and 3. The overall results indicate that during early pregnancy there is a selective modification in the histomorphological characteristics of the different regions of the rabbit oviduct.     

合作猪血液生理生化指标特性的研究

本试验对合作猪进行血液生理生化指标的测定,并将雌雄合作猪进行比较。测定结果表明,合作猪大多数血液生理生化指标性别间差异不显著(P>0.05),但多数测定项目不同日龄间差异极显著(P<0.01)或显著(P<0.05)。     

兴义市退化天然草地改良试验初报

研究结果表明,退化天然草地通过补播,鲜草产量每公顷提高６８％,经ｔ检验差异显著（ｐ＜００１）。施肥试验组与对照比较,各处理差异极显著（ｐ＜００１）,其中每公顷施１８７５ｋｇ尿素效果最佳。刈割试验与对照比较差异极显著（ｐ＜００１）,鲜草产量每公顷提高６１１％。     

INTRAVASCULAR ULTRASOUND CONTRAST MEDIA

Intravascular ultrasound contrast media are substances that increase the echogenicity of blood. Although not yet completely explored, the clinical applications of intravascular ultrasound contrast media are cardiologic, such as for chamber opacification and myocardial perfusion imaging, the assessment of vascular diseases in general and the study of tumor vessels. Gas-filled bubbles are the preferred echo-enhancing contrast media. Research in this field is concentrating on the creation of very small, stable and non-toxic bubbles, capable of surviving pulmonary transit and appear into the left heart and peripheral vessels. Contrast provided by such media is visible on grey-scale images of the heart and also enhances Doppler signals. The potential clinical applications and the problems related to the creation of ultrasound contrast media suitable for clinical use are reviewed and illustrated by examples of contrast injections performed on patients.     

中药饲料添加剂对犬生长性能和生理生化指标的影响

目的：选取断奶期八哥犬40只,探讨中草药饲料添加剂对犬生长性能和饲料转化的影响。方法：将中药按1％比例添加到实验组犬日粮中。饲喂体重相近的幼犬8周,对照组喂基础日粮。每隔10d测定1次犬的各项生理生化指标。结果：中草药饲料添加剂能明显增加犬血中白细胞、淋巴细胞、红细胞、蛋白质和血红蛋白（P〈0．05）含量,降低血清脂肪含量（P〈0．05）,提高犬的日增重、日采食量和食物利用率（P〈0．05）,促进小肠吸收（P〈0．05）,促消化（P〈0．05）。     

CORRELATION OF ARTICULAR CARTILAGE THICKNESS MEASUREMENTS MADE WITH MAGNETIC RESONANCE IMAGING,MAGNETIC RESONANCE ARTHROGRAPHY,AND COMPUTED TOMOGRAPHIC ARTHROGRAPHY WITH GROSS ARTICULAR CARTILAGE THICKNESS IN THE EQUINE METACARPOPHALANGEAL JOINT

Osteoarthritis of the metacarpophalangeal joint is common cause of lameness in equine athletes, and is hallmarked by articular cartilage damage. An accurate, noninvasive method for measuring cartilage thickness would be beneficial to screen for cartilage injury and allow for prompt initiation of interventional therapy. The objective of this methods comparison study was to compare computed tomographic arthrography (CTA), magnetic resonance imaging (MRI), and magnetic resonance arthrography (MRA) measurements of articular cartilage thickness with gross measurements in the metacarpophalangeal joint of Thoroughbred horses. Fourteen cadaveric, equine thoracic limbs were included. Limbs were excluded from the study if pathology of the metacarpophalangeal articular cartilage was observed with any imaging modality. Articular cartilage thickness was measured in nine regions of the third metacarpal bone and proximal phalanx on sagittal plane MRI sequences. After intra‐articular contrast administration, the measurements were repeated on sagittal plane MRA and sagittal CTA reformations. In an effort to increase cartilage conspicuity, the volume of intra‐articular contrast was increased from 14.5 ml, to maximal distention for the second set of seven limbs. Mean and standard deviation values were calculated, and linear regression analysis was used to determine correlations between gross and imaging measurements of cartilage thickness. This study failed to identify one imaging test that consistently yielded measurements correlating with gross cartilage thickness. Even with the use of intra‐articular contrast, cartilage surfaces were difficult to differentiate in regions where the cartilage surfaces of the proximal phalanx and third metacarpal bone were in close contact with each other.