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PubMed2000

Cytokine mRNA in the joints and draining lymph nodes of rats with adjuvant arthritis and effects of cyclosporin A.

TNF-alpha and IL-1beta promote leukocyte recruitment to arthritic joints and may contribute to cartilage degradation while regulatory cytokines such as IL-4 and IL-1RA may in part determine the course of arthritis. Here we report the pattern of TNF-alpha, IL-1beta, IL-6, IFN-gamma, IL-1RA, and IL-4 mRNA expression, detected by RT/PCR, in the talar joint and draining popliteal lymph node (PLN) of rats with adjuvant arthritis (AA). Levels of TNF-alpha and IFN-gamma mRNA were increased in the PLN before clinical signs of arthritis. This was followed by increases in IL-1beta and IL-1RA mRNA at d9 and IL-6 mRNA at d12. PLN IL-1RA mRNA levels were positively correlated with those of IL-1beta and TNF-alpha throughout d5-d20. IL-4 mRNA levels were highest on days 7 and 20. In the synovium, a small increase in TNF-alpha, IL-1beta, and IL-6 mRNA was detected on d5 then again on d12. Maximal synovial TNF-alpha levels were reached on d20, while IL-1beta peak expression was on d16 and IL-6 on d14. IL-4, IL-1RA, and IFN-gamma mRNA was undetectable in the synovium. Cyclosporin treatment for 4 days, initiated at the height of arthritis, rapidly decreased clinical disease, and decreased migration of neutrophils and T lymphocytes into the joints. Yet no significant effect of CyA was observed on inflammatory cytokine expression, although the correlation between PLN IL-1RA and IL-1beta or TNF-alpha was lost in treated animals. Thus there is a variable pattern of cytokine gene expression in rat AA, the undetectable IL-4 and IFN-gamma mRNA in synovium being analogous to human rheumatoid arthritis.

Animals↗
PubMed1999

Intra-articular IL-4 gene therapy in arthritis: anti-inflammatory effect and enhanced th2activity.

Gene therapy has been explored as a potential method for treating chronic inflammatory diseases such as rheumatoid arthritis. To determine the efficacy of intra-articular IL-4 gene therapy in an animal model of arthritis using a retroviral vector, a retrovirus encoding rat IL-4 (DA-IL-4) was engineered, purified and concentrated to high titer (>/=109 CFU/ml). Infectivity and expression levels were demonstrated in vitro using cultured fibroblast-like synoviocytes. Efficacy was evaluated in the rat adjuvant arthritis model. DA-IL-4 or DA-beta-gal retrovirus was injected into the intra-articular joint space of the right ankle on day 12 after immunization. Three days after joint injection, the injected paw contained increased levels of IL-4 compared with control or with the contralateral uninjected paw, demonstrating successful transgene expression. Surprisingly, 8 days after treatment IL-4 levels continued to increase in the injected and contralateral paw compared with DA-beta-gal-treated animals. Serum IL-4 levels were also elevated in DA-IL-4-treated rats. RT-PCR studies demonstrated that the transgene was expressed in the injected ankle but not in the contralateral joint. IL-4 gene therapy resulted in a significant reduction in paw swelling and decreased radiographic evidence of bone destruction. This is the first demonstration of successful intra-articular retroviral gene treatment using a therapeutic gene. In addition to its anti-inflammatory effect, this study supports the potential application of intra-articular gene therapy as a method for enhancing systemic Th2 function.

Animals↗
PubMed2002

Effect of cold air therapy in relieving spasticity: applied to spinalized rabbits.

STUDY DESIGN: Before-After trial measured prior to cold air therapy, immediately following, after 30 and 60 min. OBJECTIVE: To determine the effect of cold air therapy in relieving spasticity, the optimal intramuscular temperature, and the duration of spasticity relief attained by cold air therapy. SETTING: Clinical research laboratory, Seoul, Korea. SUBJECT: Forty-six spastic paraplegic rabbits with spinal cord injury. METHODS: Spastic paraplegia was induced by transection of spinal cord in 46 rabbits. Cold air was applied to triceps surae muscles for 30 min at three different intramuscular temperatures (25, 30 and 32.5 degrees C). Clinical parameters of spasticity (muscle tone, Babinski's sign, muscle stretch reflex and ankle clonus) and electrophysiologic parameters (F/M ratio and H/M ratio) were measured immediately following, after 30 and 60 min. RESULTS: In the 32.5 degrees C group, relief in spasticity lasted less than 30 min. In the 30 and 25 degrees C groups, the decrease in spasticity lasted for at least 30 min clinically. The spasticity relief was observed only immediately following treatment when measured electrophysiologically. However, six out of 16 cases (37.5%) in the 25 degrees C group showed complete motor conduction block. CONCLUSION: To relieve spasticity with cold air therapy, the intramuscular temperature should be maintained at 30 degrees C. The duration of spasticity relief lasted from between 30-60 min after cold air therapy. We certify that all applicable institutional and governmental regulations concerning the ethical use of animals were followed during the course of this research.

Animals↗
PubMed1999

Effects of dorsolateral spinal lesions on stretch reflex threshold and stiffness in awake cats.

Measurements of threshold angle and incremental dynamic stiffness (IDS) were derived from triceps surae stretch reflexes, elicited by ramp and hold flexion at the ankle joint of four cats that were tested while awake. Stretch reflexes were assessed from trials that began from different ankle joint start positions or were matched using a post-hoc analysis for initial background force during testing sessions before and following unilateral lesions of the dorsolateral funiculus at levels ranging from T13 to L3. Unilateral lesions of the dorsolateral funiculus (DLF) produced significant ipsilateral decreases in stretch reflex threshold and increases in reflex gain, measured as incremental dynamic stiffness (IDS). ANCOVA testing indicated that the reduction in threshold, but not the increase in IDS, was dependent upon the level of background force. Reflex testing from different start angles demonstrated that DLF lesions diminished the correlation between threshold and IDS. Intravenous infusion of ketamine dose-dependently reduced IDS, compared with testing in the unanaesthetized state. Postoperative reflex testing during infusion of ketamine at 22.2 mg/kg per h, when electromyographic responses were reduced to 24% of control levels, abolished differences in IDS between the ipsilateral and contralateral hindlimbs. These and related observations suggest that the postoperative increase in IDS in awake animals was not due to an increase in passive stiffness.

Anesthetics, Dissociative↗
PubMed2001

Adjuvant-induced joint inflammation causes very rapid transcription of beta-preprotachykinin and alpha-CGRP genes in innervating sensory ganglia.

Neuropeptides synthesized in dorsal root ganglia (DRG) have been implicated in neurogenic inflammation and nociception in experimental and clinical inflammatory arthritis. We examined the very early changes in response to adjuvant injection in a rat model of unilateral tibio-tarsal joint inflammation and subsequent monoarthritis. Within 30 min of adjuvant injection ipsilateral swelling and hyperalgesia were apparent, and marked increases in beta-preprotachykinin-A (beta-PPT-A) and alpha-calcitonin gene-related peptide (CGRP)-encoding mRNAs were observed in small-diameter L5 DRG neurones innervating the affected joint. This response was augmented by recruitment of additional small-diameter DRG neurones expressing beta-PPT-A and CGRP transcripts. The increased mRNA was paralleled by initial increases in L5 DRG content of the protein products, substance P and calcitonin gene-related peptide. Within 15 min of adjuvant injection there were increases in electrical activity in sensory nerves innervating a joint. Blockade of this activity prevented the rapid induction in beta-PPT-A and CGRP mRNA expression in DRG neurones. Increased expression of heteronuclear (intron E) beta-PPT-A RNA suggests that increases in beta-PPT-A mRNA levels were, at least in part, due to transcription. Pre-treatment with the protein synthesis inhibitor cycloheximide had no effect upon the early rise in neuropeptide mRNAS: This and the rapid time course of these changes suggest that increased sensory neural discharge and activation of a latent modulator of transcription are involved.

Animals↗
PubMed2002

Early alterations in the collagen meshwork and lesions in the ankles are associated with spontaneous osteoarthritis in guinea-pigs.

OBJECTIVE: The purpose of this study was to evaluate matrix changes in knee cartilage prior to development of surface disruptions and to examine the ankle for evidence of osteoarthritis (OA)-like lesions. DESIGN: Guinea-pig ankles and knees were examined histologically or viewed with polarization microscopy to reveal changes in orientation of the collagen fibers. RESULTS: The medial femoral condyles were virtually free of histologic changes at 3 months of age. Changes were present by 6 months. Medial tibial plateau histologic changes were seen at 3 months which became more pronounced with age. Alterations in the collagen meshwork corresponding to areas of proteoglycan (PG) loss were noted in animals with an intact articular surface as early as 3 months. Histologic changes were noted in the ankles as early as 3 months of age which included surface disruptions, cell loss and loss of PG staining. Only knee joint composite histology scores were significantly elevated at 3 months while both knee and ankle scores were significantly elevated at 6 months. Knee and ankle joint scores were not different from each other at 6 months. CONCLUSIONS: Alterations in the orientation of the collagen network of the cartilage correlated with Safranin-O loss suggesting that alterations in collagen:PG interactions play a role in the early phases of the OA process and precede frank histologic changes in the articular surface. The results in this study report for the first time OA-like lesions occurring spontaneously in articular cartilage of the ankle in the guinea-pig.

Aging↗
PubMedDate not supplied

The effect of implanting gentamicin-impregnated polymethylmethacrylate beads in the tarsocrural joint of the horse.

OBJECTIVE: To determine the effect of intra-articular gentamicin-impregnated polymethylmethacrylate (PMMA) beads inserted in the equine tarsocrural joint on the synovial fluid, synovial lining, and cartilage, and to determine the peak and sustainable gentamicin concentrations in synovial fluid and plasma. STUDY DESIGN: Pharmacokinetic, cytologic, and histologic study of the effect of gentamicin-impregnated PMMA on normal equine tarsocrural joints. ANIMALS: Five healthy adult horses. METHODS: Gentamicin-impregnated PMMA bead strands (3 strands each of 40 beads, with each strand containing 100 mg gentamicin) were surgically inserted into one radiographically normal tarsocrural joint in 5 horses. Each horse had both joints flushed with 1 L of lactated Ringer's solution before bead administration. Synovial fluid total protein concentration, white blood cell (WBC) count, gentamicin concentration, synovial histology, cartilage integrity, and cartilage glycosaminoglycan (GAG) concentrations were determined. RESULTS: Gentamicin concentration (mean +/- SEM peak concentration, 27.9 +/- 2.27 microg/mL) occurred in the first 24 hours and remained above 2 microg/mL for 9 days. Gentamicin concentrations in control joints and the plasma remained below detectable levels. The synovial fluid WBC count for treated joints was increased compared with control joints for 72 hours, but was similar at day 6. The synovial protein concentration in gentamicin-treated joints remained increased for 21 days. Synovium in treated joints had diffuse synovitis, whereas control joints had less fibrovascular proliferation. Superficial cartilage erosion was present in all treated joints. There was no difference in the GAG content of treated and control joint cartilage. CONCLUSIONS: Short-term implantation of gentamicin (300 mg)-impregnated PMMA beads can provide therapeutic levels of gentamicin (>2 microg/mL) in the normal tarsocrural joint for 9 days; however, gentamicin-impregnated PMMA beads induce synovitis and superficial cartilage erosion. CLINICAL RELEVANCE: Temporary intra-articular administration of antibiotic-impregnated PMMA may be an effective way to treat septic joints that require constant high concentrations of antibiotics.

Absorbable Implants↗
PubMed1996

Ankle stance angle: a functional index for the evaluation of sciatic nerve recovery after complete transection.

This study attempted to develop a motor functional index, ankle stance angle (ASA), to assess rat sciatic nerve regeneration subsequent to autografting. ASA, 50 degrees in normal rats, is the ankle joint angle at the mid-stance phase of the gait cycle. In a nerve graft group, a 1-cm segment of the right sciatic nerve was transected and then repaired with nerve autograft. In an ungrafted group, the nerve gap was left unrepaired. ASA measured 4 months after surgery was statistically significantly larger in the nerve graft group (36 degrees) than in the ungrafted group (22 degrees). The results suggest that ASA is more sensitive than sciatic function index in detecting functional recovery after a complete sciatic nerve lesion. ASA also showed a significant correlation with the passive range of ankle joint motion and gastrocnemius muscle weight. The study concluded that ASA is a reliable index for assessment of regeneration of rat sciatic nerve after a complete lesion. The intra-rater reliability (r = 0.97 and 0.90) and inter-rater reliability (r = 0.85) tests performed support the conclusions.

Animals↗
PubMed1998

Force-sharing among the primary cat ankle muscles.

Force-sharing measurements among the cat ankle extensors have been used for the past 20 years to elucidate the mechanisms underlying normal movement control and to study the force-sharing among synergistic muscles. Despite these efforts, many questions have eluded satisfactory explanation. Specifically, there has been great debate to what degree the soleus muscle is activated during low level locomotion, and whether the force-sharing among the ankle extensors is primarily caused by central or peripheral factors. We have measured the forces and corresponding electromyo-graphical activities in the soleus, gastrocnemius, plantaris, and tibialis anterior in more than 20 cats and for a variety of movements. Based on these measurements, and additional information obtained on the structural and functional properties of the cat ankle muscles, we conclude that the peak soleus forces are virtually maximal for all speeds of locomotion, despite an apparent submaximal level of activation at slow speeds. Furthermore, we found that the force-sharing among the soleus and gastrocnemius encompasses the entire possible range; from large soleus forces and zero gastrocnemius forces during still standing, to large gastrocnemius forces and no soleus forces during a high-frequency paw shake. Finally, we support the idea that shifts in force-sharing from one muscle to the other are primarily caused by central factors; the peripheral factors, although appealing when considering the large differences in size, morphology, and fibre type distribution, are likely only of secondary importance.

Animals↗
PubMed1986

Relationship of high intensity step-up lighting to bone ash and growth plate closure of the tarso-metatarsus in turkeys.

The reduced lameness observed in turkeys reared in a high intensity step-up (HISU) lighting programme as compared to a low intensity step-down (LISD) lighting regimen cannot be explained by differences in the inorganic matrix of the bone, because the proportions of bone ash, bone ash calcium, and bone ash phosphorus did not differ between lighting programmes. At 17 weeks of age, there was a significant difference in the proportion of closed growth plates in males reared on the HISU programme rather than on LISD lighting. These results support the hypothesis that HISU lighting reduces lameness by promoting earlier growth plate closure of long bones.

Animals↗
PubMed1991

Hydrogenated oil decreases tissue concentrations of n-6 polyunsaturated fatty acids and may contribute to dyschondroplasia in broilers.

1. In a factorial design of dietary treatments, male Ross broilers were given diets containing soyabean oil, hydrogenated soyabean oil (as a source of trans-fatty acids) or feed fat with either 0 or 300 micrograms of added D-biotin/kg. 2. Growth to 28 d was not influenced by the dietary treatments. 3. Length of tibiotarsal bones was reduced (P less than 0.05) and severity of leg bone cartilage lesions, characteristic of dyschondroplasia, was highest (P less than 0.05) in broilers fed on diets containing hydrogenated soyabean oil. 4. Feeding hydrogenated soyabean oil lowered (P less than 0.05) the concentrations of C20:4n6 and the ratios of C20:4n6/C18:2n6 in liver and growth plate cartilage. 5. Growth plate cartilage from birds affected with dyschondroplasia contained lower proportions of prostaglandin precursor fatty acids compared with normal growth plate. 6. It is speculated that an inhibition of prostaglandin biosynthesis brought about by the presence of trans-fatty acids might contribute to the occurrence of lesions similar to dyschondroplasia.

Animal Feed↗
PubMed1999

Collagen biochemistry of avian bone: comparison of bone type and skeletal site.

1. Skeletal disorders in poultry are of considerable welfare and economic importance. The collagenous matrix in bone is involved in many human skeletal disorders, however little is known about the nature of the collagenous matrix in avian bone. 2. This paper describes an investigation of the collagen and mineral biochemistry together with the biomechanics of bone from different sites (humerus and tibiotarsus) and with differing functions (medullary and cortical bone). In vivo and in vitro studies of immature bone assessed the changes in collagen biochemistry during bone maturation. 3. The material strength of the humerus was greater than the tibiotarsus; this difference in strength was reflected in both the collagen and mineral matrix biochemistry. 4. The bone matrix of the humerus was more mature than that of the tibiotarsus, suggesting a higher level of matrix turnover in the tibiotarsus. The pyrrole collagen cross-link concentrations were positively correlated with breaking stress, in contrast to the pyridinoline cross-link concentrations, neither of which showed any correlation with bone strength. 5. The in vivo and in vitro maturation studies underline the importance of the pyrrole cross-link in avian bone and support the mechanism postulated by Kuypers et al. (1992) for the formation of the pyrrole cross-link from a lysine aldehyde and the immature cross-links HLKNL or LKNL. 6. Medullary bone had no biomechanical influence on the breaking stress of the bone. The biochemistry of the matrix was dramatically different. The high level of collagen lysine hydroxylation affected the cross-link profile and may be responsible for the narrow fibrils and disorganised matrix of this bone. 7. Avian bone matrix varies greatly with skeletal site and reflects the differing functions of bone. Further investigation of the collagenous matrix of both normal and diseased avian bone has the potential to aid our understanding of the aetiology of avian skeletal disease.

Animals↗
PubMed2002

Critical roles for interleukin 1 and tumor necrosis factor alpha in antibody-induced arthritis.

In spontaneous inflammatory arthritis of K/BxN T cell receptor transgenic mice, the effector phase of the disease is provoked by binding of immunoglobulins (Igs) to joint surfaces. Inflammatory cytokines are known to be involved in human inflammatory arthritis, in particular rheumatoid arthritis, although, overall, the pathogenetic mechanisms of the human affliction remain unclear. To explore the analogy between the K/BxN model and human patients, we assessed the role and relative importance of inflammatory cytokines in K/BxN joint inflammation by transferring arthritogenic serum into a panel of genetically deficient recipients. Interleukin (IL)-1 proved absolutely necessary. Tumor necrosis factor (TNF)-alpha was also required, although seemingly less critically than IL-1, because a proportion of TNF-alpha-deficient mice developed robust disease. There was no evidence for an important role for IL-6. Bone destruction and reconstruction were also examined. We found that all mice with strong inflammation exhibited the bone erosion and reconstruction phenomena typical of K/BxN arthritis, with no evidence of any particular requirement for TNFalpha for bone destruction. The variability in the requirement for TNF-alpha, reminiscent of that observed in treated rheumatoid arthritis patients, did not appear genetically programmed but related instead to subtle environmental changes.

Animals↗
PubMed1999

Development of lyme arthritis in mice deficient in inducible nitric oxide synthase.

Nitric oxide (NO) is a powerful antimicrobial agent and an important regulatory molecule of the innate immune response. To determine if NO has a role in experimental Lyme disease, arthritis-resistant DBA/2J and arthritis-susceptible C3H/HeJ mice were bred to be genetically deficient for inducible NO synthase (iNOS). Following footpad injection of Borrelia burgdorferi, arthritis was similar between iNOS-deficient and control animals regardless of their genetic background. Histologic examination and arthritis severity scores of ankles revealed no differences in arthritis development between iNOS-deficient and control animals. Despite being deficient in a key antimicrobial agent, iNOS-deficient mice had tissue levels of B. burgdorferi similar to those in control mice. Thus, NO does not have a critical role in susceptibility to Lyme arthritis through tissue damage via an overexuberant inflammatory response, nor is it required in resistance through the clearance of spirochetes from tissues.

Animals↗
PubMed2005

Small clades at the periphery of passerine morphological space.

Among passerine birds (order Passeriformes), tribe- to family-level clades with five or fewer species are more frequent than one would expect from a homogeneous speciation and extinction process. Previous analyses also suggested that small clades tend to be marginal geographically and/or ecologically. In this study, I use principal component (PC) scores based on eight log-transformed measurements of the wing, tail, leg, and beak to test the hypothesis that small clades (<or=5 species) occupy peripheral positions in morphological space. Species in smaller clades exhibited higher absolute deviations and greater standard deviations on PC axes 4, 6, and 7, reflecting peripheral positions associated with relatively long toes, sometimes in contrast with short legs, and relatively small beaks compared with other birds. These extreme morphological characters are related to foraging on hard substrates, such as rock or bark, or feeding from perched positions or in dense vegetation. The implication that these small clades are protected from extinction at the periphery of morphological and, by inference, ecological space suggests that more detailed studies of the evolution and ecology of species in small clades should be a priority.

Adaptation, Physiological↗
PubMed2004

Synchrotron microangiography with no contrast agent.

Coherent x-rays from synchrotron sources are increasingly used in non-conventional radiological techniques ('phase-contrast' radiology). Our experiments demonstrate that by using white (unmonochromatic) radiation and a time-resolving system, it is possible to image microscopic details of moving blood vessels in different live animals without using any contrast agent. The images have excellent contrast plus unprecedented spatial resolution for microangiography (< 10 microm). This result is likely to impact many different areas of biological and medical research and of diagnostic radiology.

Angiography↗
PubMed2002

Chronic intrathecal baclofen treatment and withdrawal: I. Changes in ankle torque and hind limb posture in normal rats.

This study evaluated reflex excitability and locomotor changes during chronic intrathecal infusion of the GABAb agonist baclofen (ITB) and its withdrawal, in the rat. We observed sustained velocity dependent decreases in ankle torque during four weeks of ITB treatment. These changes were correlated with a significant reduction of the EMG burst magnitude time locked to the dynamic phase of ankle dorsiflexion during the first ITB treatment week. However, a considerable recovery of EMG magnitude was observed during the third and fourth weeks of treatment. During baclofen withdrawal, significantly increased velocity dependent ankle torque was observed for 4 weeks. These increases in ankle torque were correlated with increased magnitudes of EMG time locked to the dynamic phase of ankle rotation. Measures of hind limb axis and base of support were obtained using analysis of footprints on a treadmill during ITB treatment and withdrawal periods. During ITB treatment and for up to 7 weeks of withdrawal, hindlimb axis and base of support were significantly altered compared with vehicle controls. These studies were performed to provide a foundation for evaluation of treatment and withdrawal in the setting of experimental chronic contusion spinal cord injury.

Animals↗