Chicken's best friend? Livestock guardian dog bonding with free-ranging chickens.

Growth in the free-range and pastured egg industries has increased globally, necessitating improvements in predator control. Some egg producers are turning to the use of livestock guardian dogs (LGD; Canis familiaris) to protect hens from predation. We worked on a property where pastured layer hens were protected by two Maremma LGDs that were released from their chicken enclosure for 2-3 nights a week. GPS tracking showed that the dogs were more strongly bonded to people than the chickens, spending most of their time at night (96.1% of location data) close to the farmhouse and only 0.09% near their chicken paddock. Despite this lack of attendance, we found no change in the paddock space use by chickens with or without the dogs present (P = 0.999). Furthermore, camera trapping revealed 40 red fox (Vulpes vulpes) events over the 46-d monitoring period, with less fox activity on nights when the LGDs were allowed to roam the property and motion-activated spotlights were also deployed (P = 0.048). An online survey of 59 poultry producers found strong belief in the effectiveness of LGDs, although half the respondents (52%) indicated that they were still experiencing predation issues. There was no association with the reported degree of human bonding of their LGDs, but respondents were more likely to report current issues with predators if they owned 100 or more chickens (P = 0.031). The present case study as well as the farmer survey have identified that LGDs can be strongly bonded to people. Although there was no evidence of subsequently increased risk of predation, bonding with people could draw LGDs away from the animals they should be defending, with predation risk for poultry likely to depend on how far away LGDs move from their livestock.

Isolation of Cryptococcus neoformans var. grubii (serotype A) and C. magnus from the nasal lining of free-ranging quokkas (Setonix brachyurus).

Cryptococcus species are environmental yeasts, with a worldwide distribution and remarkable environmental adaptation. Although many species do not cause disease, C. neoformans and C. gattii are causative agents of cryptococcosis, a life threatening infection and a significant public health problem worldwide. Infection especially affects immunocompromised animals and humans. In wildlife, cryptococcosis appears to be more prevalent in captive populations. The objective of this study was to assess whether apparently healthy quokkas (Setonix brachyurus) harbor Cryptococcus spp. Using cultural and molecular methods, we studied yeasts isolated from nasal swabs collected from 130 free-ranging quokkas on Rottnest Island (RI, n = 97) and the mainland (n = 33) of Western Australia. Unspeciated Cryptococcus spp. (from four quokkas), C. neoformans var. grubii (serotype A) (two quokkas) and C. magnus (one quokka) were isolated from the nasal lining of apparently healthy quokkas from RI. Cryptococcus neoformans var. grubii was isolated from animals captured in a human-populated area on RI. There was no significant effect of the presence of Cryptococcus on the results of haematology, blood chemistry, peripheral blood cell morphology or clinical examination. To the best of our knowledge, this is the first documented isolation of C. neoformans var. grubii (serotype A) and C. magnus in a free-ranging macropod in Western Australia. The public health implications of this finding should be further explored.

Charnley low-friction arthroplasty: survival patterns to 38 years.

We studied survival to 38 years after Charnley low-friction arthroplasty of the hip. We used revision as an end-point, while adopting a policy of regular follow-up and early revision for radiological changes alone if indicated. Between November 1962 and June 2005, 22,066 primary low-friction arthroplasties (17,409 patients) had been performed at Wrightington Hospital by more than 330 surgeons. By June 2006, 1001 (4.5%) hips had been revised and 1490 patients (2662 hips, 12%) had died. At 31 years, where a minimum of 40 hips were still attending follow-up, survival with revision for infection as an endpoint was 95%, for dislocation 98%, for a fractured stem 88.6%, for a loose stem 72.5% and for a loose acetabular component 53.7%. Wear and loosening of the ultra-high-molecular-weight polyethylene acetabular component were the main long-term problems. We conclude that regular follow-up after hip replacement is essential and that all operative findings should be recorded at revision.

Increasing patients' body mass. Are the criteria for testing stemmed femoral components in total hip arthroplasty still valid?

The increasing incidence of obesity in the population is a topic of current interest. This trend is reflected in patients undergoing primary Charnley hip replacement. Over a 21 year period from January 1986 to October 2006, during which 6910 primary operations were performed, the body mass of patients increased at a mean rate of 0.48 kg/year. The findings suggest that the test criteria for the endurance of stemmed femoral components be modified. The maximum load should be increased from 2.3 kN to 2.5 kN to reflect patients' increasing weight. The duration of the test should be increased from 5 x 10(6) cycles during which the 'femoral component shall not fracture' to 10 x 10(6) cycles in order to reflect not only the patients' activity level but also the 4-11 year period at risk for stem fracture, and so 'reflect developing clinical experience'.

The angle-bore acetabular component and dislocation after revision of a failed total hip replacement.

We reviewed 1039 revision total hip replacements where an angle-bore acetabular component was used. After a mean follow-up of nine years (0 to 20.6), the incidence of revision for dislocation was 2.1% (22 revisions), a success rate of 97.9%. In 974 revisions, where the indication was other than dislocation, the success rate was 98.5%. Of the 65 revisions for dislocation, 58 (89.2%) were successful after the first revision and a further five after the second revision, an overall success of 96.9%. Two patients elected to have their implants removed. Dislocation after revision of failed total hip replacement is a complex issue. There is often no single cause and no simple solution. The angle-bore acetabular component, in combination with a 22.225-mm diameter femoral head, offers a high level of success.

The Charnley hip replacement -- 43 years of clinical success.

The Charnley low-frictional torque arthroplasty of the hip with 22.225 mm diameter head and thick ultra high molecular weigh polyethylene cup, both components grouted with cold curing acrylic cement, has reached 43 years of clinical success. Follow-up past 30 years is now available. Over 96% of patients are satisfied with the result. Post operative activity level is a reflection of patient selection. The neuropathic nature of the new joint does not reflect the mechanical state of the arthroplasty: regular follow-up with good quality radiographs is essential. Revisions may have to be undertaken for asymptomatic radiographic changes: a principle that must be understood and accepted before the primary procedure. The long-term problems are wear and cup loosening and strain shielding of the proximal femur. Long-term success will be further extended by understanding and practical application of the principles at the primary procedure and use of low wear materials for the articulation. The operation of total hip arthroplasty marks the beginning and not the end of treatment.

Low-friction arthroplasty of the hip using alumina ceramic and cross-linked polyethylene. A 17-year follow-up report.

We report the results of our continued review of 11 total hip arthroplasties using 22.225 mm alumina ceramic femoral heads on a Charnley flanged stem, articulating with chemically cross-linked polyethylene. There was an initial bedding-in of up to 0.41 mm at the articular surface in the first two years. This had not progressed further, at a minimum follow-up of 15 years. Radiographically no femoral or acetabular component showed loosening or osteolysis.

Does the environmental background (intensive v. outdoor systems) influence the behaviour of piglets at weaning?

Under intensive pig husbandry, outdoor systems offer a more complex physical and social environment compared with indoor systems (farrowing sheds). As the rearing environment affects behavioural development, it can, therefore, influence behavioural responses of pigs to stressful environments in later stages of production. We tested how the rearing environment influenced behavioural responses to a novel arena test in piglets on the day that they were weaned and mixed into large groups. We recorded video footage and compared the behavioural responses of 30 outdoor-raised and 30 farrowing shed-raised piglets tested in an experimental arena and sequentially exposed to four challenges (each for 5 min) on the day of weaning. Quantitative and qualitative behavioural measures were recorded using time budgets and scoring demeanour or 'qualitative behavioural expression' (using Qualitative Behavioural Assessment (QBA)). When held in isolation (challenge 1), both groups were scored as more 'scared/worried', while outdoor-raised piglets spent more time eating and jumping against the arena walls. Both groups interacted with a plastic ball (challenge 2: exposure to a novel object) during which they were scored as more 'playful/curious' than other challenges. When a food bowl was introduced (challenge 3), farrowing shed-raised piglets were more interested in playing with the food bowl itself, whereas outdoor-raised piglets spent more time eating the feed. Finally, there were no significant differences in social behaviour (challenge 4: introduction of another piglet) between the two groups in terms of the latency to contact each other, amount of time recorded engaged in aggressive/non-aggressive social interactions or QBA scores. Although piglets spent 30% of their time interacting with the other piglet, and half of this time (47%) was engaged in negative interactions (pushing, biting), the levels of aggression were not different between the two groups. Overall, outdoor-raised piglets ate more and were scored as more 'calm/passive', whereas farrowing shed-raised piglets spent more time investigating their environment and were scored as more 'playful/inquisitive'. In conclusion, we did not find differences in behaviour between outdoor-raised and farrowing shed-raised piglets that would highlight welfare issues. The differences found in this study may reflect conflicting affective states, with responses to confinement, neophobia and motivation for exploration evident.

The sensitivity of QBA assessments of sheep behavioural expression to variations in visual or verbal information provided to observers.

Qualitative behavioural assessment (QBA) is based on observers' ability to capture the dynamic complexity of an animal's demeanour as it interacts with the environment, in terms such as tense, anxious or relaxed. Sensitivity to context is part of QBA's integrative capacity and discriminatory power; however, when not properly managed it can also be a source of undesirable variability and bias. This study investigated the sensitivity of QBA to variations in the visual or verbal information provided to observers, using free-choice profiling (FCP) methodology. FCP allows observers to generate their own descriptive terms for animal demeanour, against which each animal's expressions are quantified on a visual analogue scale. The resulting scores were analysed with Generalised Procrustes Analysis (GPA), generating two or more multi-variate dimensions of animal expression. Study 1 examined how 63 observers rated the same video clips of individual sheep during land transport, when these clips were interspersed with two different sets of video footage. Scores attributed to the sheep in the two viewing sessions correlated significantly (GPA dimension 1: r s =0.95, P<0.001, GPA dimension 2: r s =0.66, P=0.037) indicating that comparative rankings of animals on expressive dimensions were highly similar, however, their mean numerical scores on these dimensions had shifted (RM-ANOVA: Dim1: P<0.001, Dim2: P<0.001). Study 2 investigated the effect of being given different amounts of background information on two separate groups of observers assessing footage of 22 individual sheep in a behavioural demand facility. One group was given no contextual information regarding this facility, whereas the second group was told that animals were moving towards and away from a feeder (in view) to access feed. Scores attributed to individual sheep by the two observer groups correlated significantly (Dim1: r s =0.92, P<0.001, Dim2: r s =0.52, P=0.013). A number of descriptive terms were generated by both observer groups and used in similar ways, other terms were unique to each group. The group given additional information about the experimental facility scored the sheep's behaviour as more 'directed' and 'focused' than observers who had not been told. Thus, in neither of the two studies did experimentally imposed variations in context alter the characterisations of animals relative to each other, but in Study 1 this did affect the mean numerical values underlying these characterisations, indicating a need for careful attention to the use of visual analogue scales.

Retinal pigment epithelium and photoreceptor maturation in a wallaby, the quokka.

Cell generation and the early stages of maturation of the retinal pigment epithelium (RPE) and photoreceptors were examined in a marsupial, the quokka, Setonix brachyurus. Results are presented for animals aged up to postnatal day (P)250. RPE cell generation was studied by analysis of cell number from wholemounted retinae and by tritiated thymidine (3HThy) autoradiography in sectioned material. For 3HThy autoradiography, quokkas aged P1-P200 were injected with 3HThy and killed either 6-20 hours later (pulse-kill) or at P100 or P250 (pulse-leave). The extent of pigmentation of the RPE sheet was examined from sections of embryonic and early postnatal stages. Retinae from animals aged P5 to P160 were also examined at the electron microscope. By P100, RPE cell number is within the range found in adults. New RPE cells are generated in a peripheral band which moves outwards as cells leave the cell cycle in more central locations. RPE cells thus complete their last cell division in a centre-to-periphery wave centred about the optic nerve head. At any given retinal location, RPE cells complete their last cell division earlier than the overlying layers of the neural retina. Cells of the RPE rapidly develop a mature morphology. For example, melanin granules are observed at P5 and Verhoeff's membrane (the terminal bar complex) is evident by P25. By contrast, photoreceptor development in this species is protracted; cone inner segments are observed by P40, whilst the first rod inner segments are observed at P60. Despite being generated earlier, morphological maturation of the cones appears retarded and prolonged compared with that of the rods. The last stages of RPE cell maturation occur late in development, in synchrony with the generation of rods.

Development and aging of cell topography in the human retinal pigment epithelium.

PURPOSE: To determine how regional cell density of this tissue changes with age, the authors examined the topography of the human retinal pigment epithelium (RPE) in wholemounted tissue obtained from eyes aged 12 to 89 years, donated for corneas. METHODS: The RPE, with choroid attached, was wholemounted and stained with cresyl violet. From these preparations, the authors analyzed retinal area, RPE cell number, and cell density. RESULTS: Retinal pigment epithelial cell number is highly variable between persons but does not appear to be age related. Retinal area increases until approximately 30 years of age, but beyond this age individual variation masks further enlargement. The distinctive topography of the RPE changes markedly with age. There is a modification from the relatively homogeneous cell density distribution in the youngest retinas examined toward a more heterogeneous pattern in older retinas. From mid-adolescence, a band of larger cells appears at the extreme periphery, adjacent to the ora serrata, which gradually widens so that by 90 years of age, it occupies the outermost 30% of the retinal area. Cell density is highest in the central temporal retina, adjacent to the macula in the neural retina, throughout life. Cell density values in this region increase slightly with age, and the difference between this and surrounding regions becomes more marked with age. CONCLUSIONS: With no marked change in total cell number, peripheral RPE in humans enlarges in area throughout life, but the RPE in more central regions decreases in area.

High dose rate (192)Ir afterloading brachytherapy for cancer of the vagina.

We report results of brachytherapy for carcinoma of the vagina, utilizing a Nucletron high dose rate system for Delclos Vaginal Applicators (cylinder) and Syed Template Applicators (interstitial). The linear quadratic (LQ) model was used to determine the optimum time-dose-fractionation schedules. Interstitial doses were determined at the isodose line that included gross tumour. Cylinder doses were determined either at the vaginal surface (5 cases), at 0.5 cm depth (5 cases), or at 1.0 cm depth (1 case). For the first treatment (n=19), interstitial templates were utilized in 8 patients and vaginal cylinders in 11. 11 patients received second treatments: 6 templates and 5 cylinders. The median dose of external beam radiation (n=15) was 40.0 Gy followed, after a median 23 day interval, by high dose rate brachytherapy (HDRB) of 4 fractions in 30-42 h; then a median interval gap of 25 days, followed by repeat HDRB. The median total fractionated HDRB dose per patient was 23.0 Gy (range: 6.9 Gy to 40.4 Gy; calculated low dose rate equivalent of 29.8 Gy). Tumour histologies included 14 squamous cell carcinomas, 2 adenocarcinomas, 2 melanomas, and 1 small cell tumour. Three patients experienced early brachytherapy-related complications (diarrhoea, dysuria and labial dermatitis). Three patients (15.8%) developed serious/late complications including ureteral stenosis, painful vaginal necrosis and small bowel obstruction. The first of these patients received 2 templates, the second a cylinder followed by a template and a cylinder, and the third a single cylinder. The 2 year progression-free survival was 39.3% (median 15.7 months), while the 2 year overall survival was 66.1% (median 29.9 months). (192)Ir afterloading HDRB is a feasible approach to women with vaginal cancer with acceptable toxicity and tumour response. Potential advantages include patient preference, outpatient cost-effectiveness in the case of cylinder technique, and no radiation exposure to hospital personnel. Long-term follow-up is needed to further assess late complications, and larger studies are needed to confirm our results.

Charnley low-frictional torque arthroplasty in patients under the age of 51 years. Follow-up to 33 years.

Between November 1962 and December 1990 a group of 1092 patients, 668 women and 424 men, under the age of 51 years at the time of surgery, underwent 1434 primary Charnley low-frictional torque arthroplasties and are being followed up indefinitely. Their mean age at operation was 41 years (12 to 51). At the latest review in June 2001 the mean follow-up had been for 15 years 1 month. Of the 1092 patients 54 (66 hips) could not be traced, 124 (169 hips) were known to have died and 220 (248 hips) had had a revision procedure. At a mean follow-up of 17 years and 5 months, 759 patients (951 hips) are still attending. In this group satisfaction with the outcome is 96.2%. The incidence of deep infection for the whole group was 1.67%. It was more common in patients who had had previous surgery (hemi- and total hip arthroplasties excluded), 2.2% compared with 1.5% in those who had not had previous surgery, but this difference was not statistically significant (p = 0.4). There were fewer cases of deep infection if gentamicin-containing cement was used, 0.9% compared with 1.9% in those with plain acrylic cement, but this was not also statistically significant (p = 0.4). There was a significantly higher rate of revision in patients who had had previous hip surgery, 24.8% compared with 14.1% in those who had not had previous surgery (p < 0.001). At the latest review, 1.95% are known to have had at least one dislocation and 0.4% have had a revision for dislocation. The indication for revision was aseptic loosening of the cup (11.7%), aseptic loosening of the stem (4.9%), a fractured stem (1.7%), deep infection (1.5%) and dislocation (0.4%). With revision for any indication as the endpoint the survivorship was 93.7% (92.3 to 95.0) at ten years, 84.7% (82.4 to 87.1) at 15 years, 74.3% (70.5 to 78.0) at 20 years and 55.3% (45.5 to 65.0) at 27 years, when 55 hips remained 'at risk'.

Wear of enhanced ultra-high molecular-weight polyethylene (Hylamer) in combination with a 22.225 mm diameter zirconia femoral head.

We have prospectively studied the wear of enhanced ultra-high molecular-weight polyethylene (Hylamer) in combination with a zirconia femoral head of 22.225 mm diameter on a cemented, triple-tapered, collarless, polished stem, the C Stem. The 71 patients who underwent total hip arthroplasty had a mean follow-up of six years (3 to 8). No patient died or was lost to follow-up. The clinical results were excellent with 96% of patients satisfied. There were no revisions. Two cups were considered to be loose radiologically. One was avulsed from the cement in a skiing accident, with a periprosthetic fracture of the femur, but has remained stable for more than seven years. One femur shows radiological appearances which are compatible with a healing infection. One femoral component is at risk of loosening. The mean rate of penetration of the cup was 0.22 mm/year (0.06 to 0.55). Our results appear to be within the guidelines set by the National Institute of Clinical Excellence. We have discontinued the use of Hylamer despite excellent clinical results and no revisions to date because the high initial rates of penetration did not settle to the expected low levels within the anticipated time.

The calcar femorale in cemented stem fixation in total hip arthroplasty.

The calcar femorale is a vertical plate of bone lying deep to the lesser trochanter and is formed as a result of traction of the iliopsoas which separates the femoral cortex into two distinct layers, the calcar femorale and the medial femoral cortex. They fuse together proximally to form the medial femoral neck. A stem placed centrally will abut against the calcar femorale with little or no space for cement. Clearing of the calcar will offer space for a cement layer, which will support the stem proximally on the posterior aspect. We compared two consecutive groups of Charnley low-friction arthroplasties, with and without clearing of the calcar. In 330 patients who had an arthroplasty without clearing the calcar, there were ten revisions for aseptic loosening of the stem and six other stems were considered 'definitely loose', giving a rate of failure of 4.8%. In 111 patients in whom the calcar was cleared there was only one revision for aseptic loosening and no stems were classed as 'definitely loose', giving a rate of failure of 0.9%. Survivorship analysis has again shown the need for long-term follow-up; the differences became clear after ten years but because of the relatively small numbers, statistical analysis is not yet applicable. We now clear the calcar femorale routinely and advocate optimal access to the medullary canal and insertion of the stem in the area of the piriform fossa.

Wear of the cup in the Charnley LFA in the young patient.

Since wear and loosening of the ultra-high-molecular-weight polyethylene cup are factors which limit the life of an arthroplasty we have attempted to identify factors associated with either low wear (0.02 mm/year or less) or high wear (0.2 mm/year or more). In a series of 1434 Charnley low-friction arthroplasties (1092 patients) 190 (13.2%) showed low wear while 149 (10.4%) showed high wear. We used chi-squared test to assess the significance of various factors. The significant factors of the low-wear group were female gender (p = 0.042), rheumatoid arthritis (p = 0.014), Charnley grade C (p = 0.03) and varus position of the stem (p = 0.003). The use of acetabular cement pressurisation (p = 0.07) and medialisation of the cup (p = 0.07) approached significance. In the high-wear group there was a predominance of men (p = 0.042) with osteoarthritis (p = 0.006) as the underlying hip pathology, and the stem in a valgus position (p = 0.023). Support of the cup by the rim of the acetabulum approached significance (p = 0.07). There was no statistical significance between the two groups for revision for aseptic loosening of the stem or fracture of the stem (p = 0.49). There was a highly significant difference (p < 0.0001) between the two groups for revision for wear and aseptic loosening of the cup, 5.3% compared with 39%. Changes in the cup geometry are probably sufficient to explain the increasing incidence of loosening and revisions with the increasing depth of penetration of the cup. There is much to be gained from the use of a low-wearing ceramic-ultra-high-molecular-weight combination. Tissue reaction to the polyethylene particles cannot be the cause of aseptic loosening of the stem.

Low-friction arthroplasty of the hip using alumina ceramic and cross-linked polyethylene. A ten-year follow-up report.

We report the results of our continued review of 14 hip arthroplasties using alumina ceramic femoral heads with cross-linked polyethylene cups. There have been no complications and a very low rate of penetration. This was 0.02 mm per year after an initial 'bedding-in' period of two years. There has been no change in the mean rate between our earlier study at six years and the current results at 10 to 11 years. The use of these bearing surfaces appears to reduce the potential amount of polyethylene debris and may provide the next logical stage in the development of the Charnley low-friction arthroplasty.

Charnley low-frictional torque arthroplasty of the hip. 20-to-30 year results.

We reviewed 261 patients with 320 Charnley low-friction arthroplasties who had a mean follow-up of 22 years 10 months (20 to 30). Of these, 93.9% considered the operation to be a success; 82.3% were free from pain and 11.6% had occasional discomfort. Satisfactory function was achieved in 59.6% and 62% had an excellent range of movement. The clinical results did not correlate well with the radiological appearance; radiologically loose components did not affect the clinical outcome. The main long-term problem was wear and loosening of the UHMWPE cup. Our findings suggest that the radiological appearance of the arthroplasty is a more reliable indication of the state of the arthroplasty than the clinical results.

Charnley low-friction arthroplasty with an autograft of the femoral head for developmental dysplasia of the hip. The 10- to 15-year results.

Between 1983 and 1988 we carried out 45 Charnley low-friction arthroplasties with autografts from the femoral head in 41 patients for developmental dysplasia of the hip. The preoperative radiographs were assessed for the severity of DDH according to the classifications of Crowe et al, Hartofilakidis et al and Sharp. The postoperative and follow-up radiographs were analysed for coverage of the socket by the graft, for loosening and for the outcome of the fixation of the bone graft. Two patients died (two hips) at four and seven years after THR from causes unrelated to the surgery and were excluded from the final radiological analysis. The mean age of the patients at the time of operation was 46 years 3 months. The autograft of the femoral head covered a mean 26% (16 to 35) of the acetabular component. All the grafts united. Some degree of resorption of the bone graft occurred in 27 patients, and always involved the lateral part of the graft, which was beyond the margin of the socket. After a mean follow-up of 11 years there had been no revisions and 38 patients had no pain or only slight discomfort. One socket migrated and four others were fully demarcated. Our findings indicate that the Charnley LFA with an autograft of the femoral head for DDH remains successful at a follow-up of 15 years.

Stem fixation in the Charnley low-friction arthroplasty in young patients using an intramedullary bone block.

We report a prospective study of the use of intramedullary bone blocks to improve the fixation of a matt-finish femoral stem in Charnley low-friction arthroplasties. There were 379 patients (441 hips), but at a minimum follow-up of ten years there were 258 arthroplasties in 221 patients including some which had been revised. The mean age at surgery was 41 years (17 to 51) and the mean follow-up was 13.4 years (1 to 20 including the early revisions). Nine stems (3.5%) had been revised for aseptic loosening, but there were no stem fractures. Survivorship of stems was 99.2% at ten years and 94.35% at 15 and 20 years. We found that the patient's gender, the position of the stem and the experience of the surgeon all influenced the outcome. Our findings suggest that using our method of stem fixation, follow-up of over 11 years was needed to reveal the effects of endosteal cavitation of the femur, and of over 13 years to assess any divergence between the clinical and the radiological outcomes of stem fixation.