Eiliv Svalastoga

Articular cartilage changes following meniscal lesions: Repair and meniscectomy studied in the rabbit knee

A well-defined, longitudinal lesion in the avascular part of the medial meniscus of the right knee was made in 30 rabbits. After 3 months, the lesion was repaired surgically in 12 rabbits, was untreated in 12 rabbits, and a meniscectomy was performed in 6 rabbits. The articular cartilage was studied macroscopically and microscopically at 3-month intervals. Cartilage changes 3 months after meniscectomy were more pronounced than after meniscal repair or than in untreated lesions. However, meniscal repair did not reverse the cartilage changes.

Security of Patient and Study Data Associated with DICOM Images when Transferred Using Compact Disc Media

The transmission of patient and imaging data between imaging centers and other interested individuals is increasingly achieved by means of compact disc digital media (CD). These CDs typically contain, in addition to the patient images, a DICOM reader and information about the origin of the data. While equipment manufacturers attach disclaimers to these discs and specify the intended use of such media, they are often the only practical means of transmitting data for small medical, dental, or veterinary medical centers. Images transmitted by these means are used for clinical diagnosis. This has lead to a heavy reliance on the integrity of the data. This report describes attempts to alter significant patient and study data on CD media and their outcome. The results show that data files are extremely vulnerable to alteration, and alterations are not detectable without detailed analysis of file structure. No alterations to the DICOM readers were required to achieve this; changes were applied only to the data files. CDs with altered data can be readily prepared, and from the point of view of individuals viewing the images, function identically to the original manufacturer’s CD. Such media should be considered unsafe where there is a potential for financial or other gain to be had from altering the data, and the copy cannot be cross-checked with the original data.

Late gestation undernutrition can predispose for visceral adiposity by altering fat distribution patterns and increasing the preference for a high-fat diet in early postnatal life.

We have developed a sheep model to facilitate studies of the fetal programming effects of mismatched perinatal and postnatal nutrition. During the last trimester of gestation, twenty-one twin-bearing ewes were fed a normal diet fulfilling norms for energy and protein (NORM) or 50% of a normal diet (LOW). From day 3 postpartum to 6 months (around puberty) of age, one twin lamb was fed a conventional (CONV) diet and the other a high-carbohydrate-high-fat (HCHF) diet, resulting in four groups of offspring: NORM-CONV; NORMHCHF; LOW-CONV; LOW-HCHF. At 6 months of age, half of the lambs (all males and three females) were slaughtered for further examination and the other half (females only) were transferred to a moderate sheep diet until slaughtered at 24 months of age (adulthood). Maternal undernutrition during late gestation reduced the birth weight of LOW offspring (P<0·05), and its long-term effects were increased adrenal size in male lambs and adult females (P<0·05), increased neonatal appetite for fat-(P=0·004) rather than carbohydrate-rich feeds (P<0·001) and reduced deposition of subcutaneous fat in both sexes (P<0·05). Furthermore, LOW-HCHF female lambs had markedly higher visceral:subcutaneous fat ratios compared with the other groups (P<0·001). Postnatal overfeeding (HCHF) resulted in obesity (.30% fat in soft tissue) and widespread ectopic lipid deposition. In conclusion, our sheep model revealed strong pre- and postnatal impacts on growth, food preferences and fat deposition patterns. The present findings support a role for subcutaneous adipose tissue in the development of visceral adiposity, which in humans is known to precede the development of the metabolic syndrome in human adults.

Pathology and biofilm formation in a porcine model of staphylococcal osteomyelitis.

A porcine model was used to examine the potential of human and porcine Staphylococcus aureus isolates to induce haematogenously spread osteomyelitis. Pigs were inoculated in the right femoral artery with one of the following S. aureus strains: S54F9 (from a porcine lung abscess; n = 3 animals), NCTC-8325-4 (a laboratory strain of human origin; n = 3 animals) and UAMS-1 (a human osteomyelitis isolate; n = 3 animals). Two pigs were sham inoculated with saline. At 11 or 15 days post infection the animals were scanned by computed tomography before being killed and subjected to necropsy examination. Osteomyelitis lesions were present in the right hind limb of all pigs inoculated with strain S54F9 and in one pig inoculated with strain NCTC-8325-4. Microscopically, there was extensive loss of bone tissue with surrounding granulation tissue. Sequestrated bone trabeculae were intermingled with colonies of S. aureus as demonstrated immunohistochemically. By peptide nucleic acid fluorescence in situ hybridization bacterial aggregates were demonstrated to be embedded in an opaque matrix, indicating that the bacteria had formed a biofilm. Development of experimental osteomyelitis was therefore dependent on the strain of bacteria inoculated and on the formation of a biofilm.

A New Technique for Modeling of Hematogenous Osteomyelitis in Pigs: Inoculation into Femoral Artery

ABSTRACT A new inoculation technique has been developed and applied in a porcine model of juvenile hematogenous osteomyelitis. Following the success of the model, we describe the inoculation technique in detail to enable its replication in future studies. The technique was based on an anatomical feature of the femoral artery that enables inoculation into the artery using a simple surgical procedure. Inoculation in the femoral artery is advantageous because the localization of lesions constitutes a discriminative model of the naturally occurring hematogenous osteomyelitis in long bones, usually involving femur and tibia in children. The procedure was performed under general anesthesia and consisted of five major steps: (1) Exposure of the right femoral artery, (2) retrograde catheterization, (3) inoculation of bacteria, (4) hemostasis of the arterial puncture site using compression, and (5) suturing of the wound in two layers.

Changes in the relative thickness of individual subcutaneous adipose tissue layers in growing pigs

BackgroundThe thickness of the subcutaneous fat layer is an important parameter at all stages of pig production. It is used to inform decisions on dietary requirements to optimize growth, in gilts to promote longevity and finally to assist in the calculation of payments to producers that allow for general adiposity. Currently for reasons of tradition and ease, total adipose thickness measurements are made at one or multiple sites although it has been long recognized that up to three well defined layers (outer (L1), middle (L2), and inner (L3)) may be present to make up the total. Various features and properties of these layers have been described. This paper examines the contribution of each layer to total adipose thickness at three time points and describes the change in thickness of each layer per unit change in body weight in normal growing pigs.MethodsA group of nine pigs was examined using 14 MHz linear array transducer on three separate occasions. The average weight was 51, 94 and 124 kg for each successive scan. The time between scanning was approximately 4 weeks. The proportion of each layer to total thickness was modeled statistically with scan session as a variable and the change in absolute thickness of each layer per unit change in body weight was modeled in a random regression model.ResultsThere was a significant change in ratios between scans for the middle and inner layers (P < 0.001). The significant changes were seen between the first and second, and between the first and final, scan sessions. The change in thickness per unit change in body weight was greatest for L2, followed by L1 and L3.ConclusionThese results demonstrate that subcutaneous adipose layers grow at different rates relative to each other and to change in body weight and indicate that ultrasound can be used to track these differences.

Repair of three-month-old experimental meniscal lesions in rabbits

Repair of three-month-old longitudinal meniscal lesions in the central avascular portion of the knee joint was investigated in 18 rabbits. Three months after a longitudinal incision was made in the avascular portion of the meniscus, no healing was observed. At that time a full-thickness radial cut from the lesion to the joint capsule, without using synovial flaps or implants, was performed in ten of the 18 rabbits. Three months later, nine of the ten menisci had healed mainly with cartilaginous tissue, although the repaired areas were different from the normal fibrocartilage both histologically and at gross inspection. Synovitis with hyperplasia of the lining cells, which was present in all cases at the time of repair, may play an important role in the healing process.

Lymphatic transport from normal and synovitic knees in rabbits

The resorption pattern of synovial fluid through the lymphatic system from normal and synovitic knee joints in rabbits was studied with 99mtechnetium-rhenium-sulfur colloid injected intraarticularly and monitored for 14 hours with a gamma camera. On the normal side the regional lymph nodes were visualized after 1 hour and after 14 hours still 75 percent activity remained in the knee. In the synovitic knees no lymphatic transport could be detected; and the radiotracer was unstable with rapid liberation of technetium, which was excreted in the urine. This radiolysis was not found in vitro in synovitic joint fluid. The lymphatic transport from normal rabbit knees is low. We found a clear difference in lymphatic transport between normal and synovitic knee joints.

Measurement of body composition in cats using computed tomography and dual energy X-ray absorptiometry.

Dual energy X-ray absorptiometry (DEXA) is a reference method for assessing body composition but is seldom `accessible in veterinary settings. Computed tomography (CT) can provide similar body composition estimates and we propose that it can be used in body composition studies in animals. We compared CT and DEXA data from 73 healthy adult neutered domestic cats. Three approaches for measuring adipose tissue percentage from full-body CT scans were explored. By examining the frequency distribution of voxels by Hounsfield unit (HU) value, it is possible to calculate a fat index (Fat%) that is in close agreement with the fat percentages obtained from DEXA scans. Fat% values obtained by the best of the methods had a mean difference of 0.96% (95% confidence interval 0.33-1.59%) from the DEXA results. Fat% obtained by the other two methods were characterized by good correlation but poor agreement and in one of the methods, the difference between the values from the two modalities was proportional to their mean. By using CT, it is possible to obtain body composition estimates that are in close agreement with those available using DEXA. While the significance of individual Fat% measurements obtained from CT can be difficult to interpret and to compare between centers, CT can contribute to research studies concerned either with nutrition or with obesity-related disorders.

Comparison of reliability of five patellar position indices at various stifle joint angles in pelvic limbs obtained from cadavers of red foxes (Vulpes vulpes)

OBJECTIVE To compare 5 patellar position indices at various stifle joint angles in cadavers of red foxes, determine measurement reliability, and assess the suitability of these indices for clinical use. SAMPLE Pelvic limbs from cadavers of 12 red foxes (Vulpes vulpes). PROCEDURES Patellar position in each limb at 7 stifle joint angles (30° to 148°) was assessed by use of the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT), and Blackburne-Peel (BP) indices. RESULTS Values for all indices varied significantly on the basis of joint angle, but for IS and mIS indices, this was minor and nonsignificant between 52° and 130° and between 52° and 148°, respectively. The dC index increased linearly, and PT and BP indices varied polynomially with increases in stifle joint angle. Stifle joint angles measured from radiographs agreed well with the goniometrically set stifle joint angles up to approximately 100° and diverged thereafter. Intraobserver and interobserver agreement was substantial for all indices, and IS index was the most precise. CONCLUSIONS AND CLINICAL RELEVANCE IS and mIS index values were effectively independent of stifle joint angle, in contrast to dC, PT, and BP indices. The BP index varied nonsignificantly across a range of joint angles. To maximize angular accuracy, radiographs should not be obtained at joint angles > 100°. Although dC, PT, and BP indices appeared to be suitable for preoperative and postoperative evaluation of patellar position, BP index appeared to have the most promise for determination of patellar position in clinical applications.