Synovitis Subsequent to Total-Hip Arthroplasty with and Without Hydroxyapatite Coatings: A Study in Dogs

OBJECTIVE: To establish whether hydroxyapatite (HA) coatings applied to metal total-hip-replacement components increased synovitis in the coxofemoral joint of dogs. Study Design-An in vivo research trial and histologic study. ANIMALS: Twenty-three large, mixed-breed dogs. METHODS: Arthroplasty components were implanted with HA on neither stem nor cup, or with HA applied to either the femoral component or with both stem and cup having HA applied in 23 dogs. Synovial inflammation was scored 3, 6, and 12 months after surgery. Synovial membrane thickness; polyethylene particulate load; fibrin exudate; membrane edema; mitotic index; giant-cell, mononuclear histiocyte, lymphocyte, and polymorph number; and collagen degeneration were scored and statistical analyses performed. RESULTS: Operated-side synovial thickness was greatly increased relative to control. Fibrin deposition, intramembranous edema, and collagen degeneration were similar within each time interval among the various component groups. The majority of inflammatory scores among the groups were unchanged. In this 12-month study, the presence of HA coatings appear not to have a marked impact on the development of synovial inflammation. CONCLUSIONS: HA-coated components do appear to contribute somewhat to the inflammatory load within the periprosthetic environment, but this effect is not marked. CLINICAL RELEVANCE: The major advantage of HA addition to arthroplasty components is enhanced osteoconductivity around metallic surfaces. The slight increase in particulate load seen in the presence of HA coatings may contribute to the development of aseptic loosening of arthroplasty components, but is unlikely to be the major causative factor.     

Effects of Growth Factors and L-Arginine on Ischemic Skin Flaps in Rats

This study determined the effect of the polypeptide growth factors transforming growth factor-beta (TGF-β), insulin-like growth factor-I (IGF-I), and growth hormone (GH) alone and in combination with dietary L-Arginine HCL (ARG) on skin flap survival in rats. Caudally based dorsal skin flaps were created in 110 Sprague-Dawley rats. The rats were randomly assigned into three treatment groups, based on drinking water supplementation. Group 1 (n = 50) received ARG in their drinking water, group 2 (n = 50) received tap water alone, and group 3 (n = 10) received N-omega-nitro-L-arginine (L-NA) and hydralazine. Groups 1 and 2 were divided into subgroups of 10 rats each based on treatment with either: TGF-β, IGF-I, GH, or IGF-I + GH. All subgroups that received GH had significantly greater ( P <.0001) median body weight gains when compared with subgroups not receiving GH. L-arginine HCL when added to IGF-I negated the positive effects of IGF-I on both flap survival and weight gain. Although the rats in all subgroups from groups 1 and 2 had an increase in mean percent skin flap survival when compared with the water alone subgroup, only rats receiving IGF-I, or the combination of ARG with either TGF-β or GH, had statistically significant enhanced skin flap survival. Rats in group 3 did not show an increase in skin flap survival when compared with the control subgroup.     

Akabane disease in sheep

Perinatal lamb mortality, associated with malformations of the CNS due to Akabane viral infection, occurred in 4 of 9 flocks of ewes lambing on 3 farms between 26 May and 14 November, 1976. Cases were restricted to ewes conceiving prior to the second week of March and lambing between 26 May and 19 July. As judged by seroconversion in sentinel flocks on 2 of the farms, field infection with Akabane virus occurred mainly between mid-February and mid-April. Malformations of the CNS occurred in 42.5%, 51.2%, 100% and 31.0% of the dead lambs examined in the affected flocks respectively. Prevalence in the 4 affected flocks, expressed as the proportion of ewes lambing which delivered at least one malformed foetus, was 6.1%, 8.4%, 88.9% and 5.7% respectively. Lamb mortality due to malformations of the CNS was 7.1%, 5.5%, 92.3% and 5.7% of lambs born. Age-specific prevalence was calculated for 3 of the 4 flocks and 2-year-old ewes accounted for 71.4% and 76.9% of total cases respectively in 2 flocks, whereas in one flock malformations occurred at equivalent frequencies throughout several older age groups. Birthweights of affected lambs were usually significantly lighter than those of unaffected lambs of similar sex and birth-type, and their mean duration of gestation was slightly, and significantly, prolonged. Micrencephaly (88.1% of cases) and hydrocephalus (68.7% of cases) were the outstanding pathological features of the malformations with hydranencephaly, microgyria, porencephaly and attenuation of the spinal cord occurring at much lower frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Medial Saphenous Fasciocutaneous Free Flap in Dogs

The purpose of this study was to identify the angiosome of the medial saphenous artery and vein and to evaluate the use of this cutaneous angiosome as a free skin flap in the dog. In phase 1 of this study, selective angiography of the medial saphenous artery performed in six canine cadavers showed that the skin covering the entire medial femorotibial area, the distal half of the caudal head of the sartorius muscle, and the gracilis muscle were perfused by the medial saphenous artery. In phase 2, a medial saphenous fasciocutaneous island flap was raised and sutured back to the skin edges of the donor wound in three dogs. One hundred percent survival of all of the flaps occurred. In phase 3, a medial saphenous fasciocutaneous microvascular free flap was transferred to a wound that was created over the dorsal metacarpal (n = 3) or metatarsal region (n = 3). The mean length ± SD of the medial saphenous vascular pedicle was 80 ± 13 mm (n = 5); the mean diameter ± SD of the medial saphenous artery was 2.8 ± 0.2 mm (n = 5) and the mean diameter ± SD of the medial saphenous vein was 4.2 ± 0.2 mm (n = 5). One hundred percent of all flaps survived (n = 6). Selective angiography of the distal cranial tibial artery (metatarsal wounds, n = 3) and the median artery (metacarpal wound, n = 3) was performed 3 weeks after surgery. All of the vascular anastomoses were patent and neovascularization of the wound beds was present. This free flap was found to be acceptable for cosmetic reconstruction of wounds located on the distal extremity.     

Repair and Function of Synovium After Arthroscopic Synovectomy of the Dorsal Compartment of the Equine Antebrachiocarpal Joint

The reparative ability of equine synovium was determined by gross, histological, and ultrastructural examination. The functional potential of the synovium was estimated by examination of synovial cell organelles with transmission electron microscopy. Results from rested and exercised horses were compared to determine the effect of exercise on synovial healing. The response of the synovectomized joint to exercise was evaluated with a standardized lameness examination and by gross, histological, and histochemical observations of the articular cartilage. A 7-mm diameter motorized synovial resector was used to perform a subtotal synovectomy in 1 antebrachiocarpal joint of each of 8 horses; the contralateral joint served as a control. After 2 months rest, four randomly selected horses were rigorously exercised for the remainder of the study; the other four horses continued paddock rest. Lameness examinations and synovial fluid analyses were conducted at 0, 2, 30, 60, and 120 days. Synovium and articular cartilage from all horses were examined at necropsy at 120 days. None of the horses were lame during the study, and a transient synovitis occurred in the synovectomized joints. The hyaluronan concentration of treated joints decreased at 2 days but returned to normal by 60 days. Synovial fluid composition, including hyaluronan concentration, was unchanged by exercise. Significant cartilage damage was not observed in any of the joints. At 120 days, the healing synovium was devoid of villi and its subintima was fibrotic, however transmission electron microscopy confirmed that an intimal layer was present within the repair tissue. The cells within the repair tissue appeared actively engaged in both synthesis and phagocytosis. Exercise did not modify any of these findings. The results of this study suggest that 120 days after subtotal synovectomy, the joint environment was maintained and the resected synovium had evidence of restoration and increased metabolic potential. Synovectomized joints withstood exercise but synovial repair was not accelerated by exercise.     

Effect of Chemical or Electrical Activation of Bovine Oocytes on Blastocyst Development and Quality

Activation of in vitro‐matured (IVM) oocytes is essential for successful embryo production following nuclear transfer (NT) or intracytoplasmic sperm injection (ICSI). This study was designed to compare the rates of blastocyst production and embryo quality (as measured by numbers of viable cells) following parthenogenetic activation with electrical pulse or the use of two different calcium ionophores, A23187 (CA) or ionomycin (IO), with or without the addition of bovine serum albumin (BSA). IVM oocytes with a first polar body were randomly allocated to five treatment groups: CA (5 μm CA, 5 min; n = 88), CA + BSA (5 μm CA, 5 min; BSA, 5 min; n = 90), IO (5 μm IO, 5 min; n = 91), IO + BSA (5 μm IO, 5 min; BSA, 5 min; n = 86) and EL (two pulses of 1.5 kV/cm, 20 μs; n = 120). Blastocyst rates were higher (p < 0.05) for CA (54.4%), IO (51.4%) and EL (54.5%) than for IO + BSA (18.3%). Treatment CA + BSA (39.8%) did not differ from the others. There was no difference (p > 0.05) among treatments in total number of cells. However, the percentage of viable cells was reduced in CA (49.9%), CA + BSA (45.8%), IO (64.9%), IO + BSA (50.9%) compared with EL (82.7%). In summary, the addition of BSA to the IO treatment had an adverse effect on blastocyst production rates. Although there was no difference between electrical stimulation and chemical activation on blastocyst production rates, electrical activation resulted in blastocysts with a higher percentage of viable cells.     

EFFECT OF METHYLCELLULOSE ON UPPER GASTROINTESTINAL QUALITY IN DOGS

This study was performed to evaluate and optimize a small bowel contrast technique using barium and methylcellulose in dogs. Ten healthy dogs underwent both a conventional upper gastrointestinal study that used only barium and a modified study that used barium and methylcellulose. The control group received 10 mL/kg of 40% barium suspension. Experimental groups were divided into three subgroups given 15 mL/kg of different viscosities (low, moderate, and high viscosity) of 0.5% methylcellulose after 4 mL/kg of 40% barium suspension. Compared with the control group, dogs receiving methylcellulose had higher-quality upper gastrointestinal studies. Moderate viscosity of methylcellulose was superior to the other methylcellulose groups. In conclusion, the use of methylcellulose is a simple and effective method for improving the image quality in an upper GI examination.     

Development of a Free Latissimus Dorsi Muscle Flap in Cats

Anatomic and experimental evaluation of the feline latissimus dorsi muscle was performed to assess its potential use as a free muscle flap. In the anatomic study, nonselective angiography of the subscapular artery was performed in nine heparinized feline cadavers. The muscle dimensions and vascular anatomy of the dissected latissimus dorsi muscle were recorded. In the experimental study four cats underwent heterotopic transplantation of a partial latissimus dorsi flap, and three cats underwent orthotopic transplantation of a complete latissimus dorsi flap. The mean length and width of the latissimus dorsi muscle was 19.0 and 5.4 cm, respectively. The dominant vascular pedicle was the thoracodorsal artery and vein. The average length and diameter of the thoracodorsal artery was 2.7 cm and 0.6 mm, respectively. Minor vascular pedicles were provided by branches of the intercostal arteries. Numerous choke anastomoses existed between the two pedicle systems. Viability of muscle flaps based on subjective evaluation, angiography, and histopathology, was 66% and 100% in the heterotopic and orthotopic studies, respectively. Flap failure seemed to be caused by both arterial and venous thrombosis. The latissimus dorsi muscle flap met criteria required for application in microvascular reconstruction. The vascular pattern was appropriate and consistent. Donor site morbidity was low, whereas surgical accessibility was high. The muscle satisfied the physical criteria of a free flap. Long-term anastomotic patency and flap viability was shown.