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[The effect of ultra high molecular weight polyethylene particle on the tissues of joint prosthesis].

OBJECTIVE: To study the effect of the high molecular weight polyethylene on the periprosthetic tissue in vivo as to give some reference to treatment of loosening hip arthroplasty. METHODS: Every lower limb of 20 New Zealand white rabbits was implanted a Co-Cr-Mo plug in femur by intercondylar notch. 15 mg polyethylene particles, dispersed in 1.5 ml normal saline solution, were injected into one knee joint. The other knee joint was injected 1.5 ml normal saline solution as control. This procedure was repeated 2,4,6,8 and 10 weeks after the implantation. Both of two lower limbs were given a X-ray examination 10 weeks to assess if there were periprosthetic osteolysis and loosening of the plugs. All animals were killed 2 weeks afer the last injection. The distribution of polyethylene in the knee joint capsule was examined to understand if there were loosening of implants or tissue change around implants. Knee joint capsule tissues and periprosthetic tissues were examined by optical microscope. RESULTS: Nine cases formed fibrous membrane and four cases formed new bone around prostheses in experiment group. Eleven cases formed new bone and two cases formed fibrous membrane in control group (P < 0.05) The X-ray results indicated that the plugs were in distal medulla of femur. There was no sign of periprosthetic osteolysis, implants loosening or new bone formation. Optical microscope study indicated that there were a lot of polyethylene particles inside the capsule. The polyethylene particles were surrounded by multinucleated foreign-body giant cells and fibroblast. In some cases, there were fibroblasts and fibrous tissue around plug. There were no polyethylene particles and multinucleated foreign-body giant cells around plug in the marrow. There were a lot of polyethylene particles on the joint surface. The bone surface that contacted multinucleated foreign-body giant cells was coarse. CONCLUSION: Maximizing ultra high molecular weight polyethylene can restrain rabbit periprosthetic bone formation.

Animals↗

Two cases of irreducible knee dislocation occurring simultaneously in two patients and a review of the literature.

Knee dislocations normally respond to closed reduction; however, a small percentage must be reduced by open operations. A 24-year-old man exhibited typical medial joint-line puckering during repeated reduction attempts and a mild lateral displacement on roentgenograms. A 31-year-old woman had a complete dislocation of her knee, with the femur "buttonholed" through medial soft tissue and entrapped by the joint capsule. Longitudinal incision of the medial joint capsule was the method of reduction. The lateral collateral ligament and both lateral and medial menisci were intact in both cases. However, the medial collateral ligament and the anterior and posterior cruciate ligaments were avulsed from the femur and required fixation.

Adult↗

A dynamic analysis of glenohumeral motion after simulated capsulolabral injury. A cadaver model.

We used a dynamic shoulder-testing apparatus and nine fresh-frozen, entire upper extremities from cadavera to evaluate the effects of varying degrees of capsulolabral injury on the kinematics of the glenohumeral joint during abduction in the scapular plane and external rotation. Joint kinematics were recorded with use of a six-degrees-of-freedom magnetic tracking device before and after the creation of each capsulolabral lesion in a progressive manner. Dislocation did not occur after simulation of a large Bankart lesion or even after sectioning of the anterior aspect of the joint capsule. However, division of the entire joint capsule (that is, both the anterior aspect and the posterior aspect) resulted in a significant increase (p < 0.05) in posterior translation during abduction in the scapular plane, and two of the nine shoulders dislocated posteriorly. External rotation of the abducted extremity produced no increase in anterior or posterior translation.

Aged↗

Surgical approaches for inserting hemiarthroplasty of the hip.

BACKGROUND: The operation of insertion of a hemiarthroplasty to the hip refers to replacement of the femoral head with a prosthesis, whilst retaining the natural acetabulum and acetabular cartilage. The main surgical approaches to the hip for insertion of the prosthesis can be broadly categorised as either 'anterior' via the anterior joint capsule, or 'posterior' through the posterior joint capsule. OBJECTIVES: To evaluate, based on evidence from randomised controlled trials, the effects of different surgical approaches for the insertion of a hemiarthroplasty to the hip has on clinical outcomes. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group specialised register (up to February 2002). Articles of all languages were considered. SELECTION CRITERIA: All randomised controlled trials comparing insertion of a hemiarthroplasty by different surgical approaches. DATA COLLECTION AND ANALYSIS: Both reviewers independently assessed trial quality, using a 10 item scale, and extracted data. Wherever appropriate and possible, the data are presented graphically. MAIN RESULTS: One randomised trial was identified involving 114 patients. The trial had poor methodology (particularly in susceptibility to selection bias), inadequate follow-up of patients who withdrew, and there was limited reporting of results. Medical complications and mortality from six months to two years appeared greater in the posterior group; this difference in mortality, within the structure of the poor methodology, was statistically significant. No other differences were claimed to be significant. REVIEWER'S CONCLUSIONS: There is currently insufficient evidence from randomised trials to determine the optimum surgical approach for insertion of a hemiarthroplasty to the hip.

Arthroplasty, Replacement, Hip↗

[Surgical treatment of volar wrist ganglia].

OBJECTIVES: We evaluated surgery-related issues concerning the excision of volar wrist ganglia in the light of data obtained from our patients. METHODS: The study included 40 patients (10 males, 30 females; mean age 32.5 years; range 18 to 65 years) who underwent surgery for volar ganglia. All the patients had unilateral involvement. All operations were performed under axillary brachial plexus regional anesthesia in the microsurgery operating room. The mean follow-up period was 2.5 years (range 1 to 5 years). RESULTS: The ganglia originated from the radioscaphoid joint capsule in 18 patients (45%), scaphotrapezial joint capsule in 16 patients (40%), and from the flexor carpi radialis tendon in two patients (5%). The ganglia were attached to the radial artery in 26 patients (65%), in two patients (5%) the radial artery completely merged into the lesion. The pedicles could not be dissected in four patients (10%), all of whom developed recurrences. Complications included recurrences in nine patients (22%), injury to the median palmar cutaneous nerve in four patients (10%), injury to the radial artery in two patients (5%) and wrist stiffness in five patients (12.5%). No significant correlation was found between complications and experience of the operating surgeons. CONCLUSION: Considering possible dissections and interventions for complication-associated repairs, and potential recurrences, surgical removal of volar ganglia should be performed under appropriate circumstances, especially in a formal operating room.

Adolescent↗

Frozen shoulder: MR arthrographic findings.

PURPOSE: To evaluate the magnetic resonance (MR) arthrographic findings in patients with frozen shoulder. MATERIALS AND METHODS: Preoperative MR arthrograms of 22 patients (six women, 16 men; mean age, 54.7 years) with frozen shoulder treated with arthroscopic capsulotomy were compared with arthrograms of 22 age- and sex-matched control subjects without frozen shoulder. The thickness of the coracohumeral ligament (CHL) and the joint capsule, as well as the volume of the axillary recess, were measured (Mann-Whitney test). Abnormalities in the CHL, subcoracoid fat, superior glenohumeral ligament, superior border of the subscapularis tendon, long biceps tendon, and subscapularis recess were analyzed in consensus by two blinded radiologists (chi(2) test). RESULTS: Patients with frozen shoulder had a significantly thickened CHL (4.1 mm vs 2.7 mm in controls) and a thickened joint capsule in the rotator cuff interval (7.1 mm vs 4.5 mm; P < .001 for both comparisons, Mann-Whitney test) but not in the axillary recess. The volume of the axillary recess was significantly smaller in patients with frozen shoulder than in control subjects (P = .03, Mann-Whitney test). Thickening of the CHL to 4 mm or more had a specificity of 95% and a sensitivity of 59% for diagnosis of frozen shoulder. Thickening of the capsule in the rotator cuff interval to 7 mm or more had a specificity of 86% and a sensitivity of 64%. Synovitis-like abnormalities at the superior border of the subscapularis tendon were significantly more common in patients with frozen shoulder than in control subjects (P = .014, chi(2) test). Complete obliteration of the fat triangle between the CHL and the coracoid process (subcoracoid triangle sign) was specific (100%) but not sensitive (32%). CONCLUSION: Thickening of the CHL and the joint capsule in the rotator cuff interval, as well as the subcoracoid triangle sign, are characteristic MR arthrographic findings in frozen shoulder.

Adult↗

Lumbar facet pain: biomechanics, neuroanatomy and neurophysiology.

Idiopathic low back pain has confounded health care practitioners for decades. Although there has been much advance in the understanding of the biomechanics of the lumbar spine over the past 25 years, the cellular and neural mechanisms that lead to facet pain are not well understood. An extensive series of experiments was undertaken to help elucidate these mechanisms and gain a better understanding of lumbar facet pain. Biomechanic and neuroanatomic studies were performed in human cadaveric facet joints and neurophysiologic studies were performed in New Zealand White rabbits. These studies provide the following evidence to help explain the mechanisms of lumbar facet pain: (1) The facet joint can carry a significant amount of the total compressive load on the spine when the human spine is hyperextended. (2) Extensive stretch of the human facet joint capsule occurs when the spine is in the physiologic range of extreme extension. (3) An extensive distribution of small nerve fibers and free and encapsulated nerve endings exists in the lumbar facet joint capsule, including nerves containing substance P, a putative neuromodulator of pain. (4) Low and high threshold mechanoreceptors fire when the facet joint capsule is stretched or is subject to localized compressive forces. (5) Sensitization and excitation of nerves in facet joint and surrounding muscle occur when the joint is inflamed or exposed to certain chemicals that are released during injury and inflammation. (6) Marked reduction in nerve activity occurs in facet tissue injected with hydrocortisone and lidocaine. Thus, the facet joint is a heavily innervated area that is subject to high stress and strain. The resulting tissue damage or inflammation is likely to cause release of chemicals irritating to the nerve endings in these joints, resulting in low back pain.

Analgesics↗

The relationship between the extensor tendon enthesis and the nail in distal interphalangeal joint disease in psoriatic arthritis--a high-resolution MRI and histological study.

OBJECTIVES: Diffuse swelling of the distal interphalangeal (DIP) joint beyond the joint margin is a common feature of arthritis in psoriatic arthritis (PsA). The purpose of this study was to explore the microanatomical basis for the inflammation and nail disease in PsA using a combined high-resolution magnetic resonance imaging (MRI) and histological studies. METHODS: High-resolution MRIs of the DIP joint were obtained in 30 subjects [10 PsA, 10 osteoarthritis (OA) and 10 normal volunteers]. The relationship between the DIP joint capsule and associated tendon enthesis and the nail bed and root were evaluated. Histological studies to define the relationship between the normal cadaveric DIP joint capsule and the nail root were performed on the middle and ring fingers of 10 dissecting room cadavers. RESULTS: On MRI, the dorsal capsular enthesis was the epicentre of an inflammatory reaction. This extended to involve the soft tissues adjacent to the nail in 8 of 10 cases in PsA, but only 4 of 10 cases in OA where the inflammation is less intense and in none of the normal fingers. The DIP joint capsule was intimately linked with the nail complex on histology, with the dorsal, volar and lateral aspects of the nail bed being ensheathed in fibres extending from the entheses. CONCLUSION: The study suggests that the extended nature of the enthesis organ associated with the DIP joint may explain the diffuse nature of the inflammatory response around the nail in PsA. Therefore the nail is as much an integral part of the enthesis organ as it is of the skin, which has implications for a better understanding of the disease.

Adolescent↗

The spinoglenoid ligament: an anatomic study.

The spinoglenoid ligament and its anatomic variations are described in 27 shoulders from 15 cadavers. In each shoulder one or two distinct spinoglenoid ligaments originated from the base of the spine of the scapula; they inserted on the neck of the scapula or the shoulder joint capsule. In the 19 shoulders in which only one spinoglenoid ligament was present, it inserted into the neck of the scapula in 14 cases and into the shoulder joint capsule in five instances. In the eight shoulders in which there were two ligaments, one inserted into the neck of the scapula and the other into the shoulder joint capsule. We did not observe any hypertrophic spinoglenoid ligaments that may have compressed the suprascapular nerve.

Cadaver↗

[Redefinition of the proximal perichondrium and perichondrial gap in hip ultrasound imaging].

As a result of the improvement in the resolution of diagnostic sonography equipment it is possible to depict sonographic echoes of structures in the area of the preformed cartilage acetabular roof, especially in the region of the proximal perichondrium, perichondrial gap and the joint capsule that up to now have not been anatomically identified. Therefore, the question arises as to which anatomical structures these newly observed sonographic echoes can be classed with. Hip-joint NMR images of corpses were made and compared to anatomical specimen, anatomical sections and sonograms of high-resolution ultrasound equipment. Through this comparative study it was possible to demonstrate that the echo of the proximal perichondrium is anatomically consistent with the proximal perichondrium itself, parts of the joint capsule and the insertion of the musculus rectus femoris tendon. Identification of the ligamentum ischiofemorale and its separation from the labrum acetabulare, the joint capsule and the musculus rectus femoris tendon leads to better interpretation of the perichondrial gap in the sonogram. Common terms, such as "proximal perichondrium" and "perichondrial gap" obtain a new anatomical assessment. These terms, taken as a basis for knowledge of the anatomical structures, can be used as usual. There are no consequences for hip sonography today if the definition of the distinction between type III and type IV, and of the standard section is used further as the basis of sonography even if these terms have received a new anatomical classification.

Acetabulum↗

Spatial distribution of hip capsule structural and material properties.

Contemporary computational models potentially allow the practical incorporation of the effects of a joint capsule on both motion and the loads transmitted to the other parts of the joint. However, the required material properties have not been available for this purpose. To determine these properties we took both hip joints from five fresh-frozen, nondiseased cadavers. Following dissection and potting of the hemi-pelvis, distraction of the intact joint was conducted to measure the structural tangent stiffness of the joint capsule. Anatomical insertion points of the hip capsule were then recorded, and a complete capsulectomy was performed. Once excised, the capsule was sectioned into eight, approximately even sectors, and initial geometrical measurements were recorded for material property calculations. Material properties (i.e., structural tangent stiffness, failure load, ultimate strength, tangent modulus) were calculated using the load-displacement and geometric data collected for each of the sectors. This specimen-to-specimen thickness variability reveals significantly lower (p<0.01) average tangent structural stiffness values in the posterior-inferior portion of the capsule. Explorations of hip stability using numerical models can now be enhanced by incorporation of these experimental capsule data.

Aged↗

Geometric and mechanical properties of human cervical spine ligaments.

This study characterized the geometry and mechanical properties of the cervical ligaments from C2-T1 levels. The lengths and cross-sectional areas of the anterior longitudinal ligament, posterior longitudinal ligament, joint capsules, ligamentum flavum, and interspinous ligament were determined from eight human cadavers using cryomicrotomy images. The geometry was defined based on spinal anatomy and its potential use in complex mathematical models. The biomechanical force-deflection, stiffness, energy, stress, and strain data were obtained from 25 cadavers using in situ axial tensile tests. Data were grouped into middle (C2-C5) and lower (C5-T1) cervical levels. Both the geometric length and area of cross section, and the biomechanical properties including the stiffness, stress, strain, energy, and Young's modulus, were presented for each of the five ligaments. In both groups, joint capsules and ligamentum flavum exhibited the highest cross-sectional area (p < 0.005), while the longitudinal ligaments had the highest length measurements. Although not reaching statistical significance, for all ligaments, cross-sectional areas were higher in the C5-T1 than in the C2-C5 group; and lengths were higher in the C2-C5 than in the C5-T1 group with the exception of the flavum (Table 1 in the main text). Force-deflection characteristics (plots) are provided for all ligaments in both groups. Failure strains were higher for the ligaments of the posterior (interspinous ligament, joint capsules, and ligamentum flavum) than the anterior complex (anterior and posterior longitudinal ligaments) in both groups. In contrast, the failure stress and Young's modulus were higher for the anterior and posterior longitudinal ligaments compared to the ligaments of the posterior complex in the two groups. However, similar tendencies in the structural responses (stiffness, energy) were not found in both groups. Researchers attempting to incorporate these data into stress-analysis models can choose the specific parameter(s) based on the complexity of the model used to study the biomechanical behavior of the human cervical spine.

Analysis of Variance↗

Anterior instability of the shoulder due to capsular laxity.

Thirty cases of anterior instability of the shoulder are reported where the only or pre-eminent pathological condition observed at operation was an abnormal laxity of the joint capsule. Four clinical pictures emerged - recurrent distortion, recurrent subluxation, recurrent dislocation, dislocation followed by recurrent subluxation - presumably due to increasing degrees of instability. In 13 cases, surgery consisted of stabilisation of the anterior joint capsule at the neck of the glenoid with a staple, and in 17 cases, capsulo-muscular plastic surgery with the aim of reducing the excessive width of the joint capsule and shortening the subscapularis. Satisfactory results were obtained in 90% of the cases. Although the quality of the results was not conditioned by the type of surgery used, capsulo-muscular plastic surgery appears to be the best method for the correction of the pathological condition responsible for the instability.

Adolescent↗

[Combined endoscopic-radiologic examination of the knee joint].

As a back-up examination to arthroscopy of the knee joint fluoroscopy with production of x-ray films may be performed during CO2 filling of the joint. The carbon dioxide serves as a contrast medium. The method enables some of the gaps left by arthroscopy to be filled. Baker cysts and ruptures of the joint capsule can be demonstrated radiologically. At the 2nd Nuremberg Surgical Clinic 60 patients underwent examination by this method in 1980 and the first half of 1981. In 18 patients pathologic changes were found -- 12 Baker cysts and six ruptures of the knee-joint capsule. The findings were confirmed at surgery. The method was not used in cases of extensive destruction of the knee-joint capsule which had already been established clinically.

Arthroscopy↗

Monopolar radiofrequency energy effects on joint capsular tissue: potential treatment for joint instability. An in vivo mechanical, morphological, and biochemical study using an ovine model.

The purpose of this study was to evaluate the thermal effect of monopolar radiofrequency energy, a potential treatment means for joint instability, on the mechanical, morphologic, and biochemical properties of joint capsular tissue in an in vivo ovine model. The energy was applied arthroscopically to the synovial surface of the femoropatellar joint capsule of 24 sheep. The sheep were sacrificed at 0, 2, 6, and 12 weeks after surgery (6 per group). Monopolar radiofrequency energy initially caused a significant decrease in tissue stiffness and an increase in tissue relaxation properties, followed by gradual improvement in the tissue's mechanical properties by 6 weeks after surgery. Microscopic examination illustrated that radiofrequency energy initially caused collagen hyalinization and cell necrosis, followed by active tissue repair. Biochemical analysis revealed that treated collagen was significantly more trypsin-susceptibile than untreated collagen at 0 and 2 weeks after surgery, indicating early collagen denaturation. This study demonstrated that this treatment initially caused a significantly deleterious effect on the mechanical properties of the joint capsule, which was associated with partial denaturation of joint capsular tissue. This was followed by gradual improvement of the mechanical, morphologic, and biochemical properties of the tissue over time.

Animals↗

Functional topography and ultrastructure of periarticular mechanoreceptors in the lateral elbow region of the rat.

The distribution and ultrastructure of sensory nerve endings were investigated in the deep lateral elbow region of the rat. Three zones of distribution of mechanoreceptors were distinguished, each in relation to the functional architecture of the connective and muscular tissue in that area: (1) a zone with muscle spindles, Golgi tendon organs, free nerve endings and single small lamellated corpuscles ('muscle-tendon spectrum'), situated in the middle third of the supinator muscle and its superficial aponeurosis; (2) a zone with small lamellated corpuscles and free nerve endings, situated pericapsularly to the humeroradial joint capsule ('shearing spectrum'): this moderately dense, irregular connective tissue is covered by the proximal continuation of the supinator's aponeurosis, and muscle fibers insert from beneath this aponeurosis, which displays, as a part of the joint capsule, a strong collagenous tissue plate; (3) a zone with only free nerve endings within the tendon-like, most proximal part of the supinator's aponeurosis, inserting into the periosteal layer of the lateral humeral epicondyle ('endotenonial spectrum'): it is part of the joint capsule. The ultrastructure of these sensory endings is described and the distribution pattern of the mechanoreceptors observed is discussed in relation to the classification into 'muscle receptors' and 'joint receptors'.

Animals↗

Haemodynamics in acute arthritis of the knee in puppies.

In order to study the haemodynamic changes of the juvenile knee in acute arthritis, an experimental model was developed in puppies by unilateral intra-articular injections of Carragheenin solution into the knee. Tissue blood flow was studied by the tracer microsphere technique in eight dogs and simultaneous intra-articular and intraosseous pressure recordings were performed in seven other dogs. The intra-articular pressure was elevated in all arthritic knees. Hyperaemia was found in the knee-joint capsule and distal femoral metaphysis, whereas juxta-articular epiphyseal blood flow rates were not significantly changed. A decrease of femoral muscle blood flow was encountered. Intraosseous pressure recordings during venous tamponade of the knee-joint capsules suggested a qualitative change of bone vasculature in acute arthritis. The juxta-articular bone blood flow in arthritis appears to be influenced by synovial hyperaemia, synovial effusion pressure, an "inflammatory resistance factor" and the anatomical relationship of the epiphyseal vessels to the knee-joint capsule.

Acute Disease↗

Characterization of tachykinin receptors mediating plasma extravasation and vasodilatation in normal and acutely inflamed knee joints of the rat.

1. Inflammatory actions of tachykinins in normal rat knee joints were compared with those of animals with acutely inflamed joints induced by intra-articular injection of 2% carrageenan. Plasma protein extravasation in rat knee joints, measured by protein micro-turbidimetry, was induced by intra-articular perfusion of selective tachykinin receptor agonists. Changes in joint blood flow, measured by laser Doppler perfusion imaging, were produced by topical applications of selective tachykinin receptor agonists to the joint capsule. 2. Carrageenan-injected rat knee joints showed significantly higher (P < 0.001) basal plasma extravasation (56 +/- 4 micrograms ml-1, n = 5) than normal rat knee joints (10 +/- 4 micrograms ml-1, n = 6). Intra-articular perfusion of the selective neurokinin1 (NK1) receptor agonist [Sar9, Met(O2)11]-substance P (0.8 nmol min-1) for 60 min elevated the basal plasma extravasation to 90 +/- 17 micrograms ml-1 (n = 6, P < 0.001) in normal joints, and to 150 +/- 14 micrograms ml-1 (n = 5, P < 0.001) in inflamed joints. Perfusion of the selective NK1 receptor antagonist N2-[(4R)-4-hydroxy-1-(1-methyl-1H- indol-3-yl)carbonyl-L-prolyl]-N-methyl-N-phenylmethyl-3-(2-naphthyl)- L-alaninamide (FK888; 0.8 nmol min-1) for 20 min followed by co-perfusion with the NK1 receptor agonist (0.8 nmol min-1) produced complete inhibition of the NK1 receptor agonist-induced plasma extravasation in the two groups of animals (for both groups; n = 3, P < 0.001). 3. Intra-articular perfusion of the selective NK receptor agonist [Nle10]-neurokinin A4-10 (0.8 nmol min-1) and the selective NK3 receptor agonist [MePhe7]-neurokinin B (0.8 nmol min1) produced no increase in plasma extravasation in normal or in inflamed rat knee joints (n = 4 and 11, P > 0.05). 4. Topical bolus applications of the NK1 receptor agonist [Sar9, Met(O2)11]-substance P onto normal joint capsules produced dose-dependent vasodilatation expressed as a voltage increase from control level. The maximum increase in blood flow was 2.05-0.21 V from a basal voltage of 3.42 +/- 0.07 V (n = 13, P < 0.001). To a much lesser extent, administration of the NK2 receptor agonist [Nle10]-neurokinin A4-10 also produced dose-dependent vasodilatation with maximum increase of 0.46 +/- 0.08 V from a basal level of 3.38 +/- 0.1 V (n = 7, P < 0.01). Animals with acutely inflamed joints showed enhanced vasodilator responses to the NK1 and NK2 receptor agonists (for both: P vs non-inflamed joints < 0.001). Thus, the NK1 and NK2 receptor agonists produced maximum increases of 2.56 +/- 0.19 V (basal level = 5.84 +/- 0.07 V; n = 7, P < 0.001) and 1.97 +/- 0.26 V (basal level = 6.31 +/- 0.23 V; n = 11, P < 0.001), respectively. The NK3 receptor agonist [MePhe7]-neurokinin B produced no change in blood flow in normal or in inflamed rat knee joints (n = 7 and 5, P > 0.05). 5. Bolus administration of the NK1 receptor antagonist FK888 (10 pmol) alone followed 5 min later by another dose of 10 pmol FK888 (i.e. total dose of 2 x 10 pmol) applied together with the NK1 receptor selective agonist [Sar9, Met(O2)11]-substance P produced partial, but significant inhibition of the NK1 receptor agonist-induced vasodilatation in both normal (maximum response reduced by 51.9 +/- 5.4%; n = 6, P < 0.001) and inflamed rat knee joints (maximum response reduced by 49.3 +/- 6.1%; n = 5, P < 0.001). The NK2 receptor agonist [Nle10]-neurokinin A4-10-induced vasodilator responses in inflamed joints were not affected by this treatment (n = 6, P > 0.05). However, with two higher doses of FK888 (both 1 nmol), the NK1 and the NK2 receptor agonist-induced vasodilator responses were abolished in the two groups of animals (n = 6-8, P < 0.005). 6. Administration of two doses of the selective NK2 receptor antagonist (S)-N-methyl-N-[4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl) -butyl]benzamide (SR48968;...

Animals↗