A Novel Type of IDH-wildtype Glioma Characterized by Gliomatosis Cerebri-like Growth Pattern, TERT Promoter Mutation, and Distinct Epigenetic Profile

Diffuse gliomas in adults encompass a heterogenous group of central nervous system neoplasms. In recent years, extensive (epi-)genomic profiling has identified several glioma subgroups characterized by distinct molecular characteristics, most importantly IDH1/2 and histone H3 mutations. A group of 16 diffuse gliomas classified as "adult-type diffuse high-grade glioma, IDH-wildtype, subtype F (HGG-F)" was identified by the DKFZ v12.5 Brain Tumor Classifier . Histopathologic characterization, exome sequencing, and review of clinical data was performed in all cases. Based on unsupervised t -distributed stochastic neighbor embedding and clustering analysis of genome-wide DNA methylation data, HGG-F shows distinct epigenetic profiles separate from established central nervous system tumors. Exome sequencing demonstrated frequent TERT promoter (12/15 cases), PIK3R1 (11/16), and TP53 mutations (5/16). Radiologic characteristics were reminiscent of gliomatosis cerebri in 9/14 cases (64%). Histopathologically, most cases were classified as diffuse gliomas (7/16, 44%) or were suspicious for the infiltration zone of a diffuse glioma (5/16, 31%). None of the cases demonstrated microvascular proliferation or necrosis. Outcome of 14 patients with follow-up data was better compared to IDH-wildtype glioblastomas with a median progression-free survival of 58 months and overall survival of 74 months (both P <0.0001). Our series represents a novel type of adult-type diffuse glioma with distinct molecular and clinical features. Importantly, we provide evidence that TERT promoter mutations in diffuse gliomas without further morphologic or molecular signs of high-grade glioma should be interpreted in the context of the clinicoradiologic presentation as well as epigenetic profile and may not be suitable as a standalone marker for glioblastoma, IDH-wildtype.

Adult intracranial ependymoma-relevance of DNA methylation profiling for diagnosis, prognosis, and treatment

BACKGROUND

A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain unclear. Here, we retrospectively evaluate the impact of surgery and radiotherapy on outcome after molecular reclassification of adult intracranial ependymomas.

METHODS

Tumors diagnosed as intracranial ependymomas from 170 adult patients collected from 8 diagnostic institutions were subjected to DNA methylation profiling. Molecular classes, patient characteristics, and treatment were correlated with progression-free survival (PFS).

RESULTS

The classifier indicated an ependymal tumor in 73.5%, a different tumor entity in 10.6%, and non-classifiable tumors in 15.9% of cases, respectively. The most prevalent molecular classes were posterior fossa ependymoma group B (EPN-PFB, 32.9%), posterior fossa subependymoma (PF-SE, 25.9%), and supratentorial ZFTA fusion-positive ependymoma (EPN-ZFTA, 11.2%). With a median follow-up of 60.0 months, the 5- and 10-year-PFS rates were 64.5% and 41.8% for EPN-PFB, 67.4% and 45.2% for PF-SE, and 60.3% and 60.3% for EPN-ZFTA. In EPN-PFB, but not in other molecular classes, gross total resection (GTR) (P = .009) and postoperative radiotherapy (P = .007) were significantly associated with improved PFS in multivariable analysis. Histological tumor grading (WHO 2 vs. 3) was not a predictor of the prognosis within molecularly defined ependymoma classes.

CONCLUSIONS

DNA methylation profiling improves diagnostic accuracy and risk stratification in adult intracranial ependymoma. The molecular class of PF-SE is unexpectedly prevalent among adult tumors with ependymoma histology and relapsed as frequently as EPN-PFB, despite the supposed benign nature. GTR and radiotherapy may represent key factors in determining the outcome of EPN-PFB patients.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

TERT promoter mutation and chromosome 6 loss define a high-risk subtype of ependymoma evolving from posterior fossa subependymoma

Subependymomas are benign tumors characteristically encountered in the posterior fossa of adults that show distinct epigenetic profiles assigned to the molecular group “subependymoma, posterior fossa” (PFSE) of the recently established DNA methylation-based classification of central nervous system tumors. In contrast, most posterior fossa ependymomas exhibit a more aggressive biological behavior and are allocated to the molecular subgroups PFA or PFB. A subset of ependymomas shows epigenetic similarities with subependymomas, but the precise biology of these tumors and their potential relationships remain unknown. We therefore set out to characterize epigenetic traits, mutational profiles, and clinical outcomes of 50 posterior fossa ependymal tumors of the PFSE group. On histo-morphology, these tumors comprised 12 ependymomas, 14 subependymomas and 24 tumors with mixed ependymoma–subependymoma morphology. Mixed ependymoma–subependymoma tumors varied in their extent of ependymoma differentiation (2–95%) but consistently exhibited global epigenetic profiles of the PFSE group. Selective methylome analysis of microdissected tumor components revealed CpG signatures in mixed tumors that coalesce with their pure counterparts. Loss of chr6 (20/50 cases), as well as TERT mutations (21/50 cases), were frequent events enriched in tumors with pure ependymoma morphology (p < 0.001) and confined to areas with ependymoma differentiation in mixed tumors. Clinically, pure ependymoma phenotype, chr6 loss, and TERT mutations were associated with shorter progression-free survival (each p < 0.001). In conclusion, our results suggest that subependymomas may acquire genetic and epigenetic changes throughout tumor evolution giving rise to subclones with ependymoma morphology (resulting in mixed tumors) that eventually overpopulate the subependymoma component (pure PFSE ependymomas).

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

What makes a 'good group'? Exploring the characteristics and performance of undergraduate student groups

Group work forms the foundation for much of student learning within higher education, and has many educational, social and professional benefits. This study aimed to explore the determinants of success or failure for undergraduate student teams and to define a 'good group' through considering three aspects of group success: the task, the individuals, and the team. We employed a mixed methodology, combining demographic data with qualitative observations and task and peer evaluation scores. We determined associations between group dynamic and behaviour, demographic composition, member personalities and attitudes towards one another, and task success. We also employed a cluster analysis to create a model outlining the attributes of a good small group learning team in veterinary education. This model highlights that student groups differ in measures of their effectiveness as teams, independent of their task performance. On the basis of this, we suggest that groups who achieve high marks in tasks cannot be assumed to have acquired team working skills, and therefore if these are important as a learning outcome, they must be assessed directly alongside the task output.

Assessing and enhancing quality through outcomes-based continuing professional development (CPD): a review of current practice

Numerous professional bodies have questioned whether traditional input-based continuing professional development (CPD) schemes are effective at measuring genuine learning and improving practice performance and patient health. The most commonly used type of long-established CPD activities, such as conferences, lectures and symposia, have been found to have a limited effect on improving practitioner competence and performance, and no significant effect on patient health outcomes. Additionally, it is thought that the impact of many CPD activities is reduced when they are undertaken in isolation outside of a defined structure of directed learning. In contrast, CPD activities which are interactive, encourage reflection on practice, provide opportunities to practice skills, involve multiple exposures, help practitioners to identify between current performance and a standard to be achieved, and are focused on outcomes, are the most effective at improving practice and patient health outcomes.

Veterinary team interactions, part one: the practice effect

Veterinary practices have evolved since the era of solo practitioners working on one site. Today veterinary practices tend to include veterinary surgeons, veterinary nurses, receptionists and business managers, leading to the notion of the veterinary team and the rise of interprofessional working. In addition, practices have grown in size and frequently include several branches, creating a distributed team. Research regarding veterinary teamwork is lacking. This paper uses Social Network Analysis (SNA) to address this issue. SNA measures interactions between members of a network. The types of interactions in practice and the effects of practice size and location (branches) are considered. Information sharing and asking for advice are straightforward, lower order interactions. Problem solving and being influenced by another are complex, higher order interactions. Smaller practices have higher densities of interactions, implying a more cohesive team. However, individuals in smaller practices still do not interact with everyone and therefore actively choose with whom to interact. Practices with little staff rotation across branches experience limited interactions across locations. The results of this study have implications for practices aiming to expand their team, either in a single site or by acquiring more branches. Suggestions for ways to maintain and improve interactions are made.

Understanding hind limb lameness signs in horses using simple rigid body mechanics

Hind limb lameness detection in horses relies on the identification of movement asymmetry which can be based on multiple pelvic landmarks. This study explains the poorly understood relationship between hind limb lameness pointers, related to the tubera coxae and sacrum, based on experimental data in context of a simple rigid body model. Vertical displacement of tubera coxae and sacrum was quantified experimentally in 107 horses with varying lameness degrees. A geometrical rigid-body model of pelvis movement during lameness was created in Matlab. Several asymmetry measures were calculated and contrasted. Results showed that model predictions for tubera coxae asymmetry during lameness matched experimental observations closely. Asymmetry for sacrum and comparative tubera coxae movement showed a strong association both empirically (R(2)≥ 0.92) and theoretically. We did not find empirical or theoretical evidence for a systematic, pronounced adaptation in the pelvic rotation pattern with increasing lameness. The model showed that the overall range of movement between tubera coxae does not allow the appreciation of asymmetry changes beyond mild lameness. When evaluating movement relative to the stride cycle we did find empirical evidence for asymmetry being slightly more visible when comparing tubera coxae amplitudes rather than sacrum amplitudes, although variation exists for mild lameness. In conclusion, the rigidity of the equine pelvis results in tightly linked movement trajectories of different pelvic landmarks. The model allows the explanation of empirical observations in the context of the underlying mechanics, helping the identification of potentially limited assessment choices when evaluating gait.

Care and Justice orientations to moral decision making in veterinary students

An adapted version of the Moral Justification Scale was used to assess moral decision-making orientation in veterinary students, comparing sex and year of study. The Scale consists of vignettes and related statements, each of which was classified as Justice, Care for People or Care for Animals. The importance of each statement in the decision-making process was rated by 204 students on a 10-point Likert Scale. An average score of importance for Justice, Care for People and Care for Animals related statements were calculated for each individual. General inclination scores were calculated by subtracting an individual's average Care score from their average Justice score. Inclination scores suggested that two-thirds of students have a balanced approach, using Justice and Care almost equally in approaching ethical dilemmas. The majority of students, however, show an overall Justice orientation. The attitude towards the importance of Justice did not vary between students of different years or sexes. Students' attitudes towards the importance of Care for People in their decision making were, however, significantly lower for final-year students. Reasons hypothesised include the start of placements. Care for Animals scores were affected by sex, whereby females give more importance to such statements than males.

Web 2.0 and the veterinary profession: current trends and future implications for lifelong learning

The NOVICE project is an EU initiative under the Lifelong Learning Programme, which aims to develop an online, professional network to promote informal, lifelong learning within the veterinary profession, using Web 2.0 tools. To inform the development of the network, a need analysis study was undertaken with relevant stakeholders. Focus group discussions were undertaken with veterinary students and veterinarians and a survey was administered to first-year students and recent graduates. The results indicate that use of computers and the internet is ubiquitous among junior members of the profession and that use of Web 2.0 tools is increasing. Concerns raised in relation to participation in online communities include verifying the quality of information and issues around professionalism. Compared with face-to-face communities, online communities were perceived to offer a number of advantages. These include convenient access to expert advice on an international scale, as well as helping to alleviate certain barriers to participation in formal, continuing education such as time, distance and cost.

Reliability of conformational measurements in the horse using a three-dimensional motion analysis system

REASONS FOR PERFORMING STUDY

The importance of a reliable method for conformation studies is generally acknowledged, but there are only limited data on the accuracy and precision of current assessment methods.

OBJECTIVES

To assess (1) the accuracy and repeatability of marker placement, (2) influence of stance of the horse on conformational parameters, (3) practicality of a computerised motion analysis system and (4) to compare the computerised motion analysis system to photographic systems of assessment.

METHODS

Twenty-eight reflective markers placed over anatomical landmarks were located in 3D using a computerised motion analysis system and their coordinates used to calculate segment lengths and joint angles. Four experiments, involving a cadaver study, a series of repeated measures on a single Thoroughbred and repeat measurements on 108 racehorses were performed.

RESULTS

Identification of anatomical landmarks was found to introduce the biggest variation in the measurements for proximal conformation parameters with the interoperator being larger than intraoperator variation. Length measurements were least influenced by stance, with distal interphalangeal and metacarpo/metatarsophalangeal joint angles being the most variable. In some measurements, the variation between stances within a horse proved to be almost as large as between horses, rendering these parameters less useful as predictors of performance or orthopaedic health.

CONCLUSIONS

A computerised motion analysis system allows 3D assessment of conformation with high accuracy and precision. It eliminates 3 major sources of error associated with photography-based methods and increases accuracy of conformational assessment by allowing repeat measurements in a relatively short period.

POTENTIAL RELEVANCE

Studies on conformation should be viewed in the light of the limitations of the measurement technique used. The presented method maximises accuracy and precision and is a valuable basis for future studies investigating the effect of conformation on performance or orthopaedic health.

Variation in conformation in a cohort of National Hunt racehorses

REASONS FOR PERFORMING THE STUDY

Assessment of conformation is commonly used in the selection of horses for performance purposes. Little information is available on the normal range of conformational traits within the Thoroughbred population.

OBJECTIVES

To describe variations in conformation in a cohort of racing Thoroughbreds in order to provide a set of baseline standards within which conformational traits can be considered normal.

MATERIALS AND METHODS

Ninety-eight conformational parameters were measured in a cohort of 108 National Hunt racehorses using a digital motion analysis system. The measurements consisted of segment lengths, joint angles in 2D and 3D, inclinations, deviations and circumference measurements. The differences between left and right sides were determined to obtain a measure of asymmetry. Conformational parameters were related to each horse's country of origin, preferred race distance and race type.

RESULTS

The majority of parameters followed a normal distribution with the biggest relative variation in hoof related measurements and in stifle and coxal angle. All circumference measurements and the majority of the length measurements were significantly correlated with the height of the horse at the withers. No underlying pattern of combinations of conformational parameters was identified. Twenty-five per cent of the parameters showed a significant difference between left and right-sided measurements. A significant difference in girth and intermandibular width was observed between Irish and French horses.

CONCLUSIONS

Thoroughbreds differ from other breeds, not only with regard to segment lengths but also with regard to joint angles and deviations. Variation in conformational parameters was relatively small and no distinct pattern of combinations of conformational traits identified.

CLINICAL RELEVANCE

The variation in conformational measurements in Thoroughbred racehorses establishes a set of baseline measurements of conformational range against which individual horses can be assessed.

The effect of conformation on orthopaedic health and performance in a cohort of National Hunt racehorses: preliminary results

REASONS FOR PERFORMING STUDY

There is a lack of scientific data and studies on the effect of conformation on performance or on orthopaedic health.

OBJECTIVES

To investigate the relationship between conformation, injury and performance in racehorses used for racing over fences.

METHODS

Over 2 years, 108 National Hunt racehorses were followed and their medical and performance data recorded. Conformation was measured in 3D with a computerised motion analysis system. Linear multiple regression models were used to evaluate the effect of conformation on measures of race performance and stepwise forward logistic regression models to assess the effect on risk of injury.

RESULTS

An increase in intermandibular width, flexor angle of the shoulder joint and coxal angle (the angle between the ilium and ischium) was demonstrated to have a positive effect on performance. Performance decreased with increasing girth, length of the hind digit and valgus conformation of the metacarpophalangeal joint. The risk of suffering from superficial digital flexor tendon injury increased with increasing metacarpophalangeal joint angle and with carpus valgus conformation. The risk of pelvic fracture increased with valgus conformation of the tarsus and decreased with an increasing coxal angle.

CONCLUSION

Valgus deformation was demonstrated to be detrimental to performance or increased risk of injury, perhaps resulting in higher loads on musculoskeletal structures. The coxal angle was the only parameter to have an effect on both risk of injury and performance. An alignment of the muscles with the axis of the pelvis may be beneficial for force transmission and decrease the bending moment of the muscles on the bones. The statistical power of this study is limited, however it provides preliminary data necessary for the planning of a larger scale study on the effect of conformation on performance and risk of injury.

CLINICAL RELEVANCE

Studies of the effects of conformation on performance and risk of injury may aid in identifying individuals likely to perform well on the racecourse and avoid risks of injury.

Accuracy of non-invasive ICP assessment can be increased by an initial individual calibration

OBJECTIVE

In a formerly introduced mathematical model, intracranial pressure (ICP) could be non-invasively assessed using cerebral blood flow velocity (FV) and arterial blood pressure (ABP). The current study attempts to check whether the accuracy of the non-invasive ICP assessment (nICP) improves after an initial individual calibration by implanted ICP probes.

METHODS

Thirteen patients with brain lesions (35-77 years, mean: 58 +/- 13 years) were studied. FV, ABP and ICP signals were recorded at days 1, 2, 4 and 7. nICP was calculated and compared to ICP. In the first recording of each patient the (invasively assessed) ICP signal was used to calibrate the nICP calculation procedure, while the follow-up recordings were used for its validation.

FINDINGS

In 11 patients 22 follow-up recordings were performed. The mean deviation between ICP and the original nICP (+/- SD) was 8.3 +/- 7.9 mmHg. Using the calibrated method this deviation was reduced to 6.7 +/- 6.7 mmHg (P < 0.005).

CONCLUSIONS

Initial individual calibration of nICP assessment method significantly improves the accuracy of nICP estimation on subsequent days. This hybrid method of ICP assessment may be used in intensive care units in patients with initially implanted ICP probes. After removal of the probes, ICP monitoring can be continued using the calibrated nICP assessment procedure.

Assessment of dynamic changes in cerebral autoregulation

Cerebral autoregulation (CA) is a control mechanism that adjusts cerebral vasomotor tone in response to changes in arterial blood pressure (ABP) to ensure a nearly constant cerebral blood flow. Patient treatment could be optimized if CA monitoring were possible. Whereas the concept of static CA assessment is simply based on comparison of mean values obtained from two stationary states (e.g., before and after a pressure change), the evaluation of dynamic CA is more complex. Among other methods, moving cross-correlation analysis of slow waves in ABP and cerebral blood flow velocity (CBFV) seems to be appropriate to monitor CA quasi-continuously. The calculation of an "instantaneous transfer function" between ABP and CBFV oscillations in the low-frequency band using the Wigner-Ville distribution may represent an acceptable compromise in time-frequency resolution for continuous CA monitoring.

Continuous cerebral autoregulation monitoring by improved cross-correlation analysis: comparison with the cuff deflation test

OBJECTIVES

To improve the cross-correlation method for noninvasive, continuous monitoring of cerebral autoregulation, to evaluate this method in humans with intact and impaired autoregulatory capacity, and to compare it to the cuff deflation test.

DESIGN AND SETTING

Prospective study in the intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

Fourteen patients with severe head injury, six patients with subarachnoid hemorrhage, and nine healthy volunteers.

INTERVENTIONS AND MEASUREMENTS

Middle cerebral artery flow velocities and arterial blood pressure were monitored continuously. Aaslid's thigh cuff tests were performed and results were scored using Tiecks' model for autoregulation index. Data were then collected without any patient manipulation. The mean time delay between slow spontaneous oscillations of blood pressure and middle cerebral artery flow velocity was calculated by cross-correlation analysis. Data are expressed as median (lower/upper quartile).

RESULTS

Healthy subjects had a higher autoregulation index than patients, 5.0 (5.0/5.5) vs. 3.3 (2.0/4.5). Slow oscillations of blood pressure and middle cerebral artery flow velocity showed a time delay of -2.0 s (-2.7/-1.7) in healthy subjects but were almost synchronal in patients, -0.07 s (-0.5/0.45). Inter-method agreement in diagnosing an intact or impaired cerebral autoregulation was obtained in 108 of 147 examinations of autoregulation (73.5%) and was considered moderate.

CONCLUSIONS

Cross-correlation analysis may serve as a simple, noninvasive, and continuous measure of cerebral autoregulation. The time delay of -2.0[Symbol: see text]s in healthy subjects is in good agreement with other studies. Short-term autoregulation tests and monitoring techniques based on slow spontaneous oscillations should not be used interchangeably.

Evidence of bias affecting the interpretation of the results of local anaesthetic nerve blocks when assessing lameness in horses

Eighteen observers were influenced to different extents in the grades of lameness they allocated to eight horses by whether they knew that a nerve block had been administered; on a scale from 0 to 10 the mean difference in grade allocated once the observer knew a horse had been nerve-blocked was increased by 0.4. The consistency of the assessments made by the individual observers was good, with a an average of 0.6 of a grade difference when grading the same horse on two occasions. The agreement between the assessments of four orthopaedic experts was reasonable (+/-1 grade), but significantly poorer for four non-experts and 10 final year veterinary students.

Relationship between acute phase proteins and hoof horn haemorrhages in postpartum first-lactation heifers

As part of a study of the development of hoof horn haemorrhages in first-lactation heifers, measurements were made of acute phase reactants to investigate the link between the acute phase response and the development of the haemorrhages. Over a period of two years, blood samples were taken from two separate groups of heifers, weekly in the three weeks before they calved and then twice weekly until eight weeks after calving. Plasma total protein, albumin, fibrinogen, haptoglobin, seromucoid and serum iron and caeruloplasmin were measured and the relationships between the peak concentration (or activity) or the area under the curve of each acute phase reactant and the peak scores for sole or white line haemorrhages were assessed by linear regression. The results suggested that the development of the hoof horn haemorrhages observed in the study was not accompanied by an acute phase response, and the haemorrhages were therefore not primarily caused by endotoxicosis. The diets and husbandry systems used were typical of dairy farms in the UK and the results therefore suggest that a significant proportion of hoof horn haemorrhages observed in UK dairy cows may not be caused by endotoxicosis.

Tenocyte response to cyclical strain and transforming growth factor beta is dependent upon age and site of origin

The effect of strain and transforming growth factor beta on equine tendon fibroblasts (tenocytes) was assessed in vitro. Tenocytes were isolated from flexor and extensor tendons of horses from foetal to 10 years of age. These cells were cultured until confluent on collagen-coated silicone dishes. Cyclic biaxial strain of 9+/-1% was applied at 0.5 Hz for 24 hours with or without added TGFbeta1 or 3 (10 ng/ml). Proliferation and synthetic responses were dependent on the tendon of origin. Neither strain nor TGFbeta caused flexor tenocytes to proliferate significantly, while strain alone did proliferate extensor tenocytes. TGFbeta, with or without strain, increased the incorporation of [3H]-proline and the production of types I and III collagen and COMP in both cell types, although the effect on COMP production was more marked in flexor tenocytes, perhaps reflecting the higher levels found in this tendon in vivo. Immature flexor tenocytes synthesised more collagen and COMP than those from mature animals, while age had little effect in extensor tenocytes. Our results suggest that tenocytes become differentiated at an early age and present tendon-specific responses.

Biochemical characterisation of navicular hyaline cartilage, navicular fibrocartilage and the deep digital flexor tendon in horses with navicular disease

The study hypothesis was that navicular disease is a process analogous to degenerative joint disease, which leads to changes in navicular fibrocartilage and in deep digital flexor tendon (DDFT) matrix composition and that the process extends to the adjacent distal interphalangeal joint. The objectives were to compare the biochemical composition of the navicular articular and palmar cartilages from 18 horses with navicular disease with 49 horses with no history of front limb lameness, and to compare navicular fibrocartilage with medial meniscus of the stifle and collateral cartilage of the hoof. Cartilage oligomeric matrix protein (COMP), deoxyribonucleic acid (DNA), total glycosaminoglycan (GAG), metalloproteinases MMP-2 and MMP-9 and water content in tissues were measured. Hyaline cartilage had the highest content of COMP and COMP content in hyaline cartilage and tendon was higher in lame horses than in sound horses (p<0.05). The concentration of MMP-2 amount in hyaline cartilage was higher in lame horses than in sound horses. The MMP-2 amounts were significantly higher in tendons compared to other tissue types. Overall, 79% of the lame horses with lesions had MMP-9 in their tendons and the amount was higher than in sound horses (p<0.05). In horses with navicular disease there were matrix changes in navicular hyaline and fibrocartilage as well as the DDFT with potential implications for the pathogenesis and management of the condition.

Effect of foot balance on the intra-articular pressure in the distal interphalangeal joint in vitro

REASONS FOR PERFORMING STUDY

Increased joint pressure has been implicated in the progression of osteoarthritis.

HYPOTHESIS

That intra-articular pressure in the distal interphalangeal joint (DIP) is significantly higher in legs loaded with heel up (HU), low heel (TU), lateral side up (LU) and medial side up (MU) imbalance compared to the balanced position.

METHODS

Twelve elbow down limbs were compressed in a hydraulic loading jig and DIP pressure measured.

RESULTS

Elevating the heels by 5 degrees significantly increased DIP pressure. After 5 ml of contrast was injected into the joint, heel elevation caused a greater increase in DIP pressure and heel lowering decreased DIP pressure. Silicone rubber castings were taken of 20 DIP whilst under load. The articular contact area was localised on the dorsal aspect in the HU position, palmar aspect in the TU position and towards the elevated side with lateromedial imbalance.

CONCLUSIONS

Altered foot orientation, which could result from trimming and shoeing, therefore influences intra-articular pressure in the DIP and the articular contact area.

POTENTIAL CLINICAL RELEVANCE

The results support the view that a balanced foot is the ideal and that the elevated heels may be detrimental to long term viability of the DIP joint.

Comparison of radiography and scintigraphy in the diagnosis of dental disorders in the horse

Scintigraphy, with 99mTechnetium methylenediphosphonate (99mTc-MDP) and 99mTc-labelled leucocytes, was compared to radiography in the diagnosis of dental disease in the horse in a prospective case-controlled study, comprising 30 horses with clinical signs of dental disease and 30 control horses. In each case, right and left lateral, ventral and dorsal soft tissue and bone phase scintigraphic images were obtained after i.v. injection of 1 GBq/100 kg bwt 99mTc-MDP, using a gamma camera. The same views were acquired in 10 horses with clinical signs of dental disease and 12 control horses after injection of 99mTc-labelled leucocytes. Standard radiographic projections of the paranasal sinuses and of the apices of the maxillary and mandibular teeth were obtained. The scintigraphs and radiographs were assessed subjectively by 2 board-certified surgeons and one board-certified radiologist, with extensive experience of equine radiology, from who the clinical history was withheld. Sensitivity, specificity and kappa, as a measure of agreement, were calculated for the different methods. Bone phase images were also scored subjectively on a scale from 0 to 3 on the basis of isotope uptake over the teeth. Regions of interest were defined over the teeth, and normal teeth compared to diseased counterparts. Total scintigraphic counts were related to the age of the animal and to the disease process. Differences in density ratios between left and right teeth were evaluated using the Mann-Whitney Test. Dental disease was confirmed in 22 horses at surgery or postmortem examination. Horses with dental disease showed a significant increase in scintigraphic activity over the affected tooth compared to the contralateral tooth, with a typical pattern for different diseases. The sensitivity of scintigraphy with 99mTc-MDP proved to be excellent (95.5%), whereas the specificity was moderate (86.4%). In contrast, radiography had excellent specificity (95.0%) and a low sensitivity (51.5%). The greatest sensitivity and specificity were achieved by evaluating radiographs and scintigrams together. The objective scintigraphic density ratios were found to be significantly different between diseased and control horses. The results of this study suggest that, if a density ratio of 1.5 or greater between a suspected diseased tooth and its contralateral number is regarded as abnormal, only 1% false positive diagnoses and 20% false negative diagnoses will occur. In contrast, scintigraphy with 99mTc-labelled leucocytes was not very successful, due to the lack of anatomical detail provided by this technique, which made identification of the diseased tooth impossible. Accurate radiographic interpretation of dental disease presents difficulties, both in terms of missed diagnoses and mistaken diagnoses. Scintigraphy complements radiographic examination of dental structures by providing information important for accurate diagnosis and is, therefore, conceived to be essential for selection of the appropriate treatment for dental disease.

Electroencephalogram silence ratio for early outcome prognosis in severe head trauma

OBJECTIVE

To introduce the electroencephalogram silence-ratio (ESR) as a variable derived from mathematically processed electroencephalogram for early outcome prognosis in patients with severe head trauma and to comparatively assess sensitivity, specificity and predictive value vs. somatosensory evoked potentials and brainstem auditory evoked potentials.

DESIGN

Prospective, interventional study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

A total of 32 adults with severe acute head trauma (Glasgow Coma Scale score < or = 8).

METHODS AND MAIN RESULTS

In all patients, electroencephalographic recording was continuously performed by frontomastoid electrode montage for 24-96 hrs after admission to the ICU. The data were subsequently computed by fast Fourier analysis and the ESR (intervals of suppression as periods >240 msecs during which the electroencephalographic voltage did not exceed 5 microV) was displayed and recorded on a computer for further evaluation. Somatosensory evoked potentials and brainstem auditory evoked potentials were elicited during the first 2 days after admission. Outcome evaluation was performed 6 months after trauma using the Glasgow Outcome Scale and the Rappaport Disability Rating Scale. After careful artifact exclusion, the ESR depicted the highest sensitivity, specificity, and positive predictive value compared with evoked potentials. Even a highly significant correlation between outcome and ESR was found (p < .0001).

CONCLUSION

The ESR is a valuable variable showing a high reliability with respect to outcome prediction in severe head trauma with a higher predictive value than short latency somatosensory evoked potentials. Evidence exists that the ESR provides at least partial information regarding adequate cerebral oxygen delivery.

Influence of interleukin-1beta and hyaluronan on proteoglycan release from equine navicular hyaline cartilage and fibrocartilage

Proteoglycan (PG) release, in response to recombinant human interleukin-1beta (rh-IL-1beta), was measured in cartilage explants obtained from the equine distal sesamoid bone (navicular bone). Fibrocartilage from the surface of the navicular bone apposing the deep digital flexor tendon and hyaline cartilage from the surface of the navicular bone articulating with the middle phalanx were labelled with 35SO4. Hyaline cartilage from the distal metacarpus was used as a control tissue. Following radiolabel incorporation, the three cartilage types were treated with rh-IL-1beta (100 U/mL) in the presence of hyaluronan (0.2, 2, 20, 200 and 2000 microgram/mL). rh-IL-1beta-Induced PG release was measured by scintillation assay of PG-bound radiolabel. Increases in PG release of 94% (P < 0.01), 101% (P < 0.05) and 122% (P < 0.05), in response to rh-IL-1beta, were noted in fibrocartilage, navicular hyaline cartilage and metacarpal hyaline cartilage, respectively. Hyaluronan (0.2 microgram/mL) significantly reduced rh-IL-1beta-induced PG release in metacarpal hyaline cartilage (P < 0.01). In fibrocartilage and navicular hyaline cartilage, hyaluronan did not reduce PG release and at some concentrations appeared to increase PG release, although this was not statistically significant. These experiments show that (i) fibrocartilage and hyaline cartilage of the navicular bone release PGs in response to rh-IL-1beta, and (ii) hyaluronan does not prevent rh-IL-1beta-induced breakdown of navicular bone cartilage.

Radiological study to evaluate suspected scapulohumeral joint dysplasia in Shetland ponies

A radiological study was performed to test the hypothesis that osteoarthritis of the scapulohumeral joint in Shetland ponies is secondary to shoulder dysplasia. Animals were selected into 3 groups: Group 1: Shetland ponies with a radiological and clinical diagnosis of scapulohumeral osteoarthritis (n = 8); Group 2: Shetland ponies without forelimb lameness (n = 12); Group 3: Horses/ponies without a history or clinical signs of forelimb lameness (n = 22). Anatomical indices were measured from mediolateral radiographs of a scapulohumeral joint from each animal. There was a significant difference in the mean radius of curvature of the glenoid cavity of the scapula (RCG) between the 3 groups (MANOVA test, P = 0.003). The mean RCG of both Group 1 (P = 0.001) and Group 2 (P = 0.022) was significantly greater than that of Group 3. There was no significant effect of group on the radius of curvature of the humeral head or on the Conformity Index. There was a significant effect of group on the Glenoid Ratio (MANOVA test, P = 3 x 10(-6)). The mean Glenoid Ratio was significantly lower in both Group 1 (P = 2 x 10(-6)) and in Group 2 (P = 0.006) than in Group 3. These results indicate that the glenoid cavity of the scapula is 'flatter' and 'shallower' in Shetland ponies which we postulate to be a primary dysplasia in this breed.

Endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses

This study was designed to develop a reliable technique for endoscopic examination of the tarsal sheath of the lateral digital flexor tendon of horses. The anatomy of the tendon sheath and associated structures was studied in detail in cadavers before determining portals for the insertion of an arthroscope into the sheath. Approaches into the sheath through the proximal pouch and through the flexor retinaculum, at the level of the sustentaculum tali, were performed and compared in cadavers. The proximal pouch portal permitted visualisation only of the proximal half of the sheath, while the approach through the retinaculum allowed examination of the entire sheath. The normal endoscopic appearance of the tarsal sheath was studied. The endoscopic approach was subsequently used to examine and treat 5 horses with tarsal sheath tenosynovitis, including 2 cases of chronic, traumatic tenosynovitis and 3 of subacute septic tenosynovitis. Four of these horses had fragmentation of the sustentaculum tali. The technique allowed adequate examination of the sheath and debridement of adhesions and lesions within the lumen of the sheath. Fragments dorsal to the medioplantar edge of the sustentaculum tali could not be visualised endoscopically and had to be removed after widening of the wound. All 5 horses survived. Follow-up enquiries (8-31 months) revealed that the horses were all reported to be sound. Four were performing at their previous level of activity, 1 was used for hacking. The 2 cases presented with chronic tenosynovitis had residual sheath distension with no associated loss of function. A prospective study, including longer term follow-up investigation, is currently being performed.

Comparison of radiography, scintigraphy and ultrasonography in the diagnosis of a case of temporomandibular joint arthropathy in a horse

Diagnosis of temporomandibular joint disease in the horse presents a challenge to the equine veterinarian. This case report illustrates a combined imaging approach using radiography, scintigraphy and ultrasonography in a horse with severe arthropathy of the left temporomandibular joint. Radiographs were inconclusive. Scintigraphy with Tc99m methylenediphosphonate localised, but failed to characterise the disease process; ultrasonography was the only imaging method which both localised and characterised the lesion. Ultrasonography proved to be a relatively cheap, technically easy to perform and non-invasive method for the assessment of the disease.

A pharmacodynamic and pharmacokinetic study with vedaprofen in an equine model of acute nonimmune inflammation

The pharmacodynamics and enantioselective pharmacokinetics of vedaprofen were studied in six ponies in a two period cross-over study, in which a mild acute inflammatory reaction was induced by carrageenan soaked sponges implanted subcutaneously in the neck. Vedaprofen, administered intravenously at a dosage of 1 mg/kg, produced significant and prolonged inhibition of ex vivo serum thromboxane B2 (TXB2) synthesis and short-lived inhibition of exudate prostaglandin E2 (PGE2) and TXB2 synthesis. Vedaprofen also partially inhibited oedematous swelling and leucocyte infiltration into exudate. Vedaprofen displayed enantioselective pharmacokinetics, plasma concentrations of the R(-) enantiomer exceeding those of S(+) vedaprofen. The plasma concentration ratio, R:S, increased from 69:31 at 5 min to 96:4 at 3 h and plasma mean AUC values were 7524 and 1639 ng x h/mL, respectively. Volume of distribution was greater for S(+) vedaprofen, whilst elimination half-life (t(1/2beta)) and mean residence time were greater for R(-) vedaprofen. The penetration of vedaprofen into inflammatory exudate was also enantioselective. For R(-) and S(+) vedaprofen maximum concentration (Cmax) values were 2950 and 1534 ng/mL, respectively, and corresponding AUC values were 9755 and 4400 ng x h/mL. Vedaprofen was highly protein bound (greater than 99%) in both plasma and exudate. The significance of these data for the therapeutic use of vedaprofen is discussed.

Intraoperative facial nerve monitoring (IFNM) predicts facial nerve outcome after resection of vestibular schwannoma

Intraoperative facial nerve monitoring (IFNM) is a suitable technique for intraoperative facial nerve identification and dissection, especially in large vestibular schwannomas (VS) (acoustic neuroma). To evaluate its feasibility for estimating functional nerve outcome after VS resection 60 patients underwent surgery using IFNM. Out of this group the last 40 patients were included in a prospective study evaluating the prognostic value of various IFNM parameters (proximal and distal absolute EMG amplitude, stimulation threshold, and proximal-to-distal amplitude ratio) for prediction of initial postoperative facial nerve function and recovery of function. Stimulation threshold and absolute EMG amplitude proximally at the brain stem were both predictive for postoperative nerve function. Good initial facial nerve outcome (modified House Brackmann grading, mHB degree I and degree II) was found in 15/16 patients with a proximal EMG amplitude greater than 800 microV and in 19/22 patients with proximal stimulation threshold less than 0.3 mA. Sixteen of 16 patients with proximal stimulation threshold equal to or greater than 0.3 mA had moderate-to-severe facial palsy (mHB degree III or worse). Six of six patients without evokable proximal amplitude initially had insufficient nerve function (mHB degree IV). Intraoperative decrease of the proximal amplitude was associated with an unfavourable outcome, whereas distal amplitudes usually stayed unchanged. Mean distal EMG amplitudes were also found to be decreased with poor nerve function, which may mean that the tumour had already affected the nerve. A proximal amplitude of 300 microV or less and a proximal-to-distal amplitude ratio below 1:3 were found in the absence of functional recovery in 6/8 (75%) and 5/6 (83%) patients with initial mHB degree IV, respectively. Two patients with initial mHB degree IV improved to mHB degree III despite intraoperative evidence of missing functional nerve integrity. Therefore, functional recovery cannot be predicted by IFNM in all cases of anatomical nerve preservation. We conclude that a minimum follow-up period of 1 year may still be advisable even in certain patients without evidence of intraoperative functional nerve integrity.

Rheumatoid factor, anti-heat shock protein (65 kDa) antibodies and anti-nuclear antibodies in equine joint diseases

To consider the hypothesis that autoimmune mechanisms may contribute to the pathology of equine joint diseases, 3 autoimmune responses were assayed in sera and synovial fluids. IgM-rheumatoid factor and antibodies to heat shock protein 65 kDa were determined by ELISA; anti-nuclear antibodies were assayed by indirect immunofluorescence to whole cell nuclear components. All parameters showed only modest increases, if any and not in a pattern related to disease, although some statistically significant increases were detected. Group analysis showed significantly elevated synovial fluid IgM-rheumatoid factor (IgM-RF) in horses with OA (P < 0.01), traumatised joints (P < 0.01) and articular fractured bones (P < 0.001). There was no significantly increased IgM-RF in the sera of horses with joint disorders compared to control horses. Significantly raised anti-heat shock protein molecular weight 65 kDa (HSP65) antibodies were only found in the synovial fluids of the horses with traumatised joints (P < 0.001). No correlations were found between the synovial fluid and sera levels of IgM-RF or anti-HSP65 antibodies. Synovial fluid anti-HSP65 antibody and IgM-RF levels positively correlated in the OCD (P < 0.001), fracture (P < 0.01) and synovitis (P < 0.05) groups. As antibodies to HSP65 correlated with IgG concentrations in synovial fluids, it is not possible to draw conclusions on HSP roles in joint disease pathogenesis. No serum anti-nuclear antibodies (ANA) were detected by immunofluorescence using rat liver and a human epithelial cell line (HEp-2) as substrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-collagen antibodies and immune complexes in equine joint diseases

An investigation was made into the possible contribution of autoimmune mechanisms to equine arthropathies. Serum and synovial fluid (SF) immune complexes and anti-collagen Type II antibodies were measured, by ELISA, in groups of horses with naturally occurring osteoarthritis (OA), osteochondritis dissecans (OCD), bone fracture, traumatised joints, synovitis, infected joints and non-diseased (control) joints. Significantly raised anti-collagen Type II antibodies were found in osteoarthritic (P < 0.02) and traumatised joint synovial fluids (P < 0.01) compared with the control, where ten of 38 (26%) OA and five of eight (63%) traumatised joint synovial fluid samples had raised anti-collagen Type II antibodies (above mean and 2 SD of control group; P < 0.05). Significantly raised levels of C1q-binding immune complexes were found in the synovial fluids of horses with OA (P < 0.001), OCD (P < 0.02), fractured articular bone (P < 0.001), infected (P < 0.01) and traumatised joints (P < 0.001) as compared with the control horses. Raised C1q-binding activity (above mean and 2 SD of control group; P < 0.05) was shown in synovial fluids in 18 of 38 (47%) OA, four of 16 (25%) OCD, four of nine (44%) fractured bone, one of eight (14%) synovitis, two of four (50%) infected joints and seven of eight (88%) traumatised joints. No raised anti-collagen Type II antibodies or C1q-binding activity were detected in sera from any clinical group. Correlations were found, in synovial fluids, between anti-collagen Type II antibodies and C1q-binding activity in OA (P < 0.02), synovitis (P < 0.01) and infected joint (P < 0.05) groups. Within individual horses, there were no correlations between the SF and sera measurements of either anti-collagen II or C1q-binding activity. The relationship between cause and effect of these immunological findings cannot be determined; as they are common to many types of equine joint disorder it is probable that they are not an initiating factor in pathology.

Pharmacodynamics and pharmacokinetics of carprofen in the horse

The pharmacokinetics and pharmacodynamics of the nonsteroidal anti-inflammatory drug (NSAID) carprofen have been evaluated in 6 horses using a model of acute non-immune inflammation. Following intravenous administration of 0.7 mg racemic carprofen/kg bwt, mean values for pharmacokinetic parameters were 18.1 h (elimination half-life); 0.25 l/kg (volume of distribution, Vd[area]); 58.9 ml/min (clearance); and 57.9 micrograms/ml.h (area under plasma concentration time curve). Mean exudate:plasma concentration ratios exceeded 1.0 at all sampling times between 2 and 48 h. Swelling at the site of acute inflammation was significantly reduced but exudate leucocyte numbers were unchanged. Although carprofen produced moderate suppression of serum thromboxane B2 and exudate prostaglandin E2 synthesis, these effects were not related to carprofen concentrations in plasma or exudate. It was concluded that the anti-oedematous action of carprofen was not attributable to inhibition of cyclo-oxygenase.

Cellular sources of proteolytic enzymes in equine joints

Isolated equine blood and articular cells were investigated for proteolytic enzyme production by means of gel filtration and analysis on 14C-acetylated collagen and casein substrates. Significant amounts of collagenase and caseinase activity were produced by cultured synoviocytes stimulated with equine interleukin 1, although large amounts of collagenase also originated from neutrophils.

Proteolytic enzymes in equine joints with infectious arthritis

Significant amounts of collagenase and caseinase activity were detected in infected synovial fluid samples. Partial characterisation of the enzymes by gel filtration suggested that synovial fluid from cases of infectious arthritis may contain enzymes from both the synovial cells and neutrophils. This finding was also supported by analysis of sequential synovial fluid samples from 4 infected joints. In 3 joints the concentration of caseinase and in 1 joint collagenase paralleled the decline in total nucleated cell count. However, in 3 joints the concentration of collagenase remained high after the total nucleated cell count had returned to normal, suggesting that this enzyme originated from resident articular cells.

Equine chondrocyte activation by a variety of stimuli

There is increasing evidence that the chondrocyte is capable of considerable anabolic and catabolic activity. In the case of equine chondrocytes, this study demonstrates that a variety of factors involved in the pathogenesis of joint disease stimulate the production of prostaglandin E2. These include exposure to IL-1, bone fragments and LPS. In addition, an IL-1-like factor was shown to be produced by the chondrocyte itself, when stimulated by LPS, providing a possible mechanism for amplification of extra-cartilagenous signals and even autocrine control. Considered together with evidence of increased synthesis of proteoglycan molecules by chondrocytes in diseased cartilage, this offers the exciting possibility of development of therapeutic agents to assist cartilage repair.

Anaplastic sarcoma in the caudal thigh of a horse

A 16-year-old showjumping gelding was examined because of a non-painful, slowly progressive caudal thigh swelling, which was associated with 2/10th lameness at the trot. Radiography, real time beta-mode ultrasonography and gamma-scintigraphy of the caudal thigh for the presence of chip fractures, sequestrum formation and, or, abscessation were inconclusive. Radiographic examination of the chest revealed multifocal, nodular cannon ball-like opacities throughout the entire lung fields from which a diagnosis of a primary soft tissue tumour with metastasis to the thorax was made. An anaplastic sarcoma was diagnosed port mortem in the candal thigh. At no time did the horse show signs of respiratory embarrassment.

Bilateral subluxation of the pastern joint in the forelimbs of a foal

A three-month-old foal was presented with subluxation of the proximal interphalangeal joint in both forelimbs. The condition, which was considered to represent an unusual manifestation of breakdown of the suspensory apparatus, appeared to have developed as a consequence of extreme overexertion, 10 days previously. This had resulted in rupture of the palmar supporting structures of the joint; namely, the superficial distal sesamoidean ligament, the insertion of the superficial digital flexor tendon and the palmar joint capsule. Severe laxity of the flexor tendons had been present in the neonatal period, and it is postulated that this might have contributed to the development of the condition by weakening the suspensory apparatus, and placing increased strain on the suspensory ligament and its associated structures.

Interleukin-1 stimulation of equine articular cells

Prostaglandin E2 (PGE2) and stromelysin are produced by equine chondrocytes and synovial cells in vitro in response to recombinant human (rh) interleukin-1 (IL-1) alpha and beta, and equine mononuclear cell supernatants (MCS) containing IL-1. However, culture conditions are important. PGE2 concentrations increase in proportion to the concentration of fetal calf serum (FCS) in the culture medium, whereas stromelysin concentrations are inversely proportional to the concentration of FCS. Equine MCS, containing a lower concentration of IL-1 than the concentration of rhIL-1 used in these experiments, stimulated production of much higher levels of PGE2 than rhIL-1. In addition, equine MCS induced the production of broadly similar levels of PGE2 by both chondrocytes and synovial cells, whereas rhIL-1 was more active on equine synovial cells than equine chondrocytes. Although equine MCS induced both stromelysin and PGE2 production by equine articular cells, on the whole rhIL-1 failed to induce stromelysin production. This supports previous observations of species restrictions in the activity of human IL-1 on equine cells. Therefore, experiments using mammalian cells and heterologous IL-1 should be interpreted with caution.

Buprenorphine's effects on self-administration of smoked cocaine base and orally delivered phencyclidine, ethanol and saccharin in rhesus monkeys

The effects of buprenorphine on behavior reinforced by smoked cocaine base and orally delivered phencyclidine (PCP), ethanol and saccharin were compared. There were six groups of four to five rhesus monkeys. Group 1 contained four monkeys that had been trained to smoke cocaine base under progressive ratio (PR) or fixed ratio (FR) schedules. Up to eight smoke deliveries (2 mg/kg) were available during daily 3-hr sessions. Each delivery was separated by a 15-min timeout. The remaining groups received concurrent access to different combinations of orally delivered liquids as follows: group 2, PCP (0.25 mg/ml) and water; group 3, saccharin (0.03% w/v) and water; group 4, PCP and saccharin; group 5, ethanol (8% w/v) and water; and group 6, ethanol and PCP. Saline or buprenorphine (0.003, 0.012, 0.05, 0.2 and 0.8 mg/kg) injections were given i.m. 30 min before each session for 5 consecutive days. Buprenorphine produced a dose-dependent reduction in behavior maintained by PCP, ethanol or saccharin in all of the six groups. In group 1, the suppressant effects of buprenorphine on cocaine base smoking were greater in the two monkeys that responded under FR 5 schedules than in the two that responded under PR schedules. When PCP and saccharin were concurrently available (group 4), buprenorphine had a greater suppressant effect on PCP than when water was concurrently present (group 2). Buprenorphine produced nearly a complete suppression in saccharin-maintained responding at doses of 0.012 mg/kg and higher in groups 3 and 4. Buprenorphine reduced ethanol deliveries to about 50% at doses of 0.012 mg/kg and higher in group 5. When PCP and ethanol were concurrently available (group 6), buprenorphine had an effect on PCP and ethanol that was similar to that found when the drugs were available concurrently with water. These results suggest that buprenorphine suppresses behavior maintained by several drug and nondrug substances, and it further suppresses PCP-maintained behavior that is already reduced by a nondrug alternative reinforcer.

Inhibition of interleukin-1 activity by equine synovial fluid

The presence, in equine synovial fluid, of inhibitors of interleukin-1 (IL-1) activity has been investigated by means of an assay involving IL-1-mediated production of PGE2 by synovial cells. Inhibitors of IL-1 alpha and IL-1 beta were identified in normal synovial fluid and synovial fluid from two horses with early joint disease. Inhibitors of IL-1 alpha were also present in synovial fluid from two horses with long-standing joint disease. However, IL-1 beta inhibitory activity was not present in fluid from the horses with more chronic joint disease. The effect appeared to be specific for IL-1, and not a direct action on PGE2 production, as synovial fluid had no effect on lipopolysaccharide-mediated PGE2 production. It is suggested that the inhibitory activity may be involved physiologically in the control of IL-1 activity in the joint, and the loss of IL-1 inhibition may be at least as important biologically as increased production of IL-1.

Species restrictions demonstrated by the stimulation of equine cells with recombinant human interleukin-1

Equine thymocytes, which respond to equine monocyte supernatants, do not respond to stimulation with recombinant human interleukin-1 alpha and beta, and equine synovial fibroblasts show a limited response in the form of prostaglandin E2 production without any evidence of neutral metalloproteinase production. Human interleukin-1 beta was about three to ten times as active on equine synovial cells as human interleukin-1 alpha in terms of prostaglandin E2 production. This preliminary evidence would suggest that there are qualitative and quantitative differences in the way recombinant human interleukin-1 stimulates human cells and the way in which it stimulates equine cells.