DISTAL INTERPHALANGEAL ARTICULAR CARTILAGE ASSESSMENT USING LOW‐FIELD MAGNETIC RESONANCE IMAGING

The suitability of low‐field magnetic resonance (MR) imaging for assessment of articular cartilage has been questioned, based on insufficient image quality. The purposes of this study were to describe the MR anatomy of the normal distal interphalangeal (DIP) cartilage, and to evaluate the sensitivity and accuracy of low‐field MR imaging for identification of cartilage erosions that were created ex vivo. Imaging sequences included sagittal and dorsal multiple‐oblique T1‐weighted gradient‐recalled echo (GRE) and sagittal dual echo sequences. In the thickest regions, normal cartilage appeared as a trilaminar structure on high‐resolution T1‐weighted GRE sequences. All 8 mm large full‐thickness erosions were correctly identified (100% sensitivity and accuracy) using T1‐weighted GRE sequences. Sensitivity and accuracy ranged from 80% to 100% and 10% to 80%, respectively, for detecting focal full‐thickness erosions and from 35% to 80% and 35% to 60%, respectively, for detecting partial thickness erosions, using T1‐weighted GRE sequences. Superficial irregularities were not diagnosed using any sequence. Overall, fewer cartilage alterations were detected with sagittal dual echo sequences than with sagittal T1‐weighted GRE sequences. The dorsal multiple‐oblique plane was useful to detect linear dorsopalmar erosions. A combination of T1‐weighted GRE sequences in two planes has potential for identification of severe DIP cartilage erosion in anesthetized horses using low‐field MR imaging.     

ÉTUDES SUR LE MODE D'ACTION DU PHÉNYLCAR-BAMOYLOXY-2 N-ÉTHYLPROPIONAMIDE, ISOMÉRE D

Summary. 2-Phenylcarbamoyloxy-N-ethylpropionamide, D isomer (11.561 R.P.) was submitted to various physiological tests in order to characterize its properties. Although it does not affect the Hill reaction, it is able to disorganize the plant cell and inhibits tissue differentiation. It penetrates rapidly into susceptible and resistant plants, but the degradation varies with the plant family. It disappears very rapidly from susceptible species, whereas resistant plants accumulate it without any apparent damage. One of its metabolites, aniline, is present in small quantities soon after treatment but is very rapidly eliminated.
Studies showed that residues in plants were negligible at harvest.
Untersuchungen über Wirkimgsweise und Rückslände des Carbanilsäureesters des D-Milchsäure-äthylamids in Pflanzen     

In Vitro Evaluation of the Effect of Fracture Configuration on the Mechanical Properties of Standard and Novel Interlocking Nail Systems in Bending

Objective— To investigate the effect of fracture configuration on the mechanical properties of standard interlocking nails (ILNs) and a novel angle-stable ILN (ILNn) in bending.
Study Design— In vitro experimental study.
Sample Population— Synthetic tibial gap fracture bone models.
Methods— Bone models, featuring a 5 or 120 mm central defect, respectively, mimicking a simple diaphyseal and a comminuted fracture involving both metaphyses, were implanted with 6 or 8 mm screwed or bolted standard ILNs (ILN6s, ILN6b, ILN8s, ILN8b, respectively) or an ILNn. Specimens were tested in 4-point bending. Construct angular deformation (AD) and slack were statistically compared ( P <.05).
Results— With increasing gap size, standard ILN construct AD increased significantly by ∼27% in ILN8b and by up to 105% in ILN6s. Similarly, standard ILN construct slack significantly increased by ∼33% in ILN8b (from ∼4.2° to ∼5.6°) and by up to ∼130% in ILN6s (from ∼7° to ∼16°). Conversely, there was no difference in the ILNn construct AD (∼4°) regardless of gap size. ILNn AD was the lowest of all groups and occurred without slack.
Conclusions— This study demonstrated that the angle-stable ILNn provided construct stability regardless of fracture configuration, whereas the intrinsic slack of standard ILNs could jeopardize construct stability in a fracture configuration involving the metaphyses.
Clinical Relevance— Use of standard ILNs may be optimal in diaphyseal fractures where circumferential nail/cortical contact could augment repair stability. Conversely, the angle-stable ILNn may represent a reliable fracture stabilization method for diaphyseal fractures as well as fractures involving the metaphyseal regions.     

COMPARISON OF MAGNETIC RESONANCE IMAGING,COMPUTED TOMOGRAPHY,AND RADIOGRAPHY FOR ASSESSMENT OF NONCARTILAGINOUS CHANGES IN EQUINE METACARPOPHALANGEAL OSTEOARTHRITIS

We compared the ability of 1.5 T magnetic resonance imaging (MRI), computed tomography (CT), and computed radiography (CR) to evaluate noncartilaginous structures of the equine metacarpophalangeal joint (MCP), and the association of imaging changes with gross cartilage damage in the context of osteoarthritis. Four CR projections, helical single‐slice CT, and MRI (T1‐weighted gradient recalled echo [GRE], T2^*‐weighted GRE with fast imaging employing steady‐state acquisition [FIESTA], T2‐weighted fast spin echo with fat saturation, and spoiled gradient recalled echo with fat saturation [SPGR‐FS]) were performed on 20 racehorse cadaver forelimbs. Osteophytosis, synovial effusion, subchondral bone lysis and sclerosis, supracondylar lysis, joint fragments, bone marrow lesions, and collateral desmopathy were assessed with each modality. Interexaminer agreement was inferior to intraexaminer agreement and was generally moderate (i.e., 0.4<κ<0.6). Subchondral bone sclerosis scores using CT or MRI were correlated significantly with the reference quantitative CT technique used to assess bone mineral density (P<0.0001). Scores for subchondral lysis and osteophytosis were higher with MRI or CT vs. CR (P<0.0001). Although differences between modalities were noted, osteophytosis, subchondral sclerosis, and lysis as well as synovial effusion were all associated with the degree of cartilage damage and should be further evaluated as potential criteria to be included in a whole‐organ scoring system. This study highlights the capacity of MRI to evaluate noncartilaginous changes in the osteoarthritic equine MCP joint.     

Effects of fat coated rumen bypass lysine and methionine on performance of dairy cows fed a diet deficient in lysine and methionine

Two experiments were conducted to evaluate the effect of fat coated rumen bypass lysine (RPLys) and methionine (RPMet) on the lactation performance of dairy cows. In Experiment 1, three lactating cows were supplied with RPLys and fat coated DL‐Met which was highly protected (H‐RPMet) as an indigestible marker, and total fecal emission was collected for 72 h following administration. Measuring the proportional difference in fecal excretion of lysine derived from RPLys relative to methionine derived from H‐RPMet, the intestinal availability of RPLys was estimated to be 66.2%. In Experiment 2, 20 multiparous Holstein cows producing approximately 40 kg/day of milk were assigned to two treatments; fed RPLys (16 g/day as lysine) and RPMet (6.5 g/day as methionine) or none (control) from 5 to 21 weeks postpartum. The consumption of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were significantly more in the control cows throughout the experimental period. Their milk protein yield, the contents of their milk protein and milk fat were higher by 0.03 kg (P = 0.03), 0.06% (P < 0.001) and 0.11% (P = 0.07), respectively, in the treatment group compared to the control. These results suggest that the RPLys and RPMet used in this study improved the lactation performance of dairy cows.     

ECHOCARDIOGRAPHIC AND DOPPLER CHARACTERISTICS OF POSTOPERATIVE DUCTAL ANEURYSM IN A DOG

A patent ductus arteriosus (PDA) was detected in a 10-month-old Pyrenean Shepherd. The PDA was occluded with hemostatic clips. One month after surgery, an aneurysmal dilatation of the ductus was diagnosed using Doppler echocardiography. The authors present the echo-Doppler findings and the follow-up of the ductus aneurysm. The pathogenesis and significance of such an aneurysm are discussed.     

FAT‐SUPPRESSED SPOILED GRADIENT‐RECALLED IMAGING OF EQUINE METACARPOPHALANGEAL ARTICULAR CARTILAGE

The purpose was to evaluate the capacity of 1.5 T magnetic resonance (MR) imaging to assess articular cartilage in racehorses with naturally occurring metacarpophalangeal joint osteoarthritis. A sagittal, three‐dimensional spoiled gradient‐recalled echo (SPGR) with fat saturation (FS) sequence was acquired ex vivo on 20 joints. Following joint dissection, specific areas on the third metacarpal condyle were designated for subsequent sampling for histologic cartilage thickness measurement and modified Mankin scoring. Cartilage thickness was measured and cartilage signal intensity was also graded (0–3) on MR images at these selected metacarpal sites. Cartilage structure was graded (0–3) macroscopically and on MR images by two examiners in defined subregions of the proximal phalanx, third metacarpal, and proximal sesamoid bones. There was good precision (mean error 0.11 mm) and moderate correlation (r=0.44; P<0.0001) of cartilage thickness measurements between MR images (0.90±0.17 mm) and histology (0.79±0.16 mm). There was moderate correlation between modified Mankin histologic score and signal intensity of cartilage (r=0.36; P<0.01) or MR cartilage structure assessment (r=0.49, P>0.001) on SPGR‐FS. The sensitivity to detect full‐thickness cartilage erosion on MR was only moderate (0.56), and these lesions were often underestimated, particularly when linear in nature. However, the specificity to detect such lesions on MR was high (0.92). While few limitations were identified, the use of a clinically applicable SPGR‐FS sequence allows a reasonably accurate method to assess structural changes affecting the articular cartilage of the equine metacarpophalangeal joint.