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PubMed2000

The joint effect of apolipoprotein E epsilon4 and MRI findings on lower-extremity function and decline in cognitive function.

BACKGROUND: Cognitive decline and poor physical function are risk factors for disability in old age and may occur more often in subjects with the apolipoprotein E epsilon4 (ApoE-epsilon4) allele. The objective of this study was to investigate the joint effect of ApoE-epsilon4 and structural changes detected on MRI brain scans on cognitive decline and lower-extremity function. METHODS: Brain MRI (1.5 T), neuropsychological tests, and lower-extremity physical function tests were administered to World War II male veteran twins ages 69 to 80. Quantification of MRI scans used a previously published algorithm to segment brain images into total cerebral brain (TCB), cerebrospinal fluid (CSF), and white-matter hyperintensity (WMH) volumes. A short battery of physical performance tests was used to assess lower-extremity function. Ten-year changes in performance on the Mini-Mental State Exam (MMSE), the Benton Visual Retention Test (BVRT), and the Digit Symbol Substitution (DSS) test were used to assess cognitive decline. RESULTS: For the sample as a whole, the comparison of subjects by median split of total cerebral brain volume found that those with brain volumes below the median performed worse on tests of gait and balance (p < .01) and experienced greater cognitive decline on the MMSE and BVRT cognitive test batteries (both p < .01). In addition, subjects with WMH volumes above the median had poor performance on the standing balance tasks and experienced greater decline on the DSS test (p < .01). Stratified analyses revealed that the joint effect of radiological findings and the ApoE-epsilon4 allele on cognitive decline and lower-extremity function was often greater than that expected from the separate effects combined. CONCLUSIONS: We conclude that radiological findings in conjunction with ApoE-epsilon4 may single out a group at higher risk for dementia. We speculate that the observed interaction effect may be due to increased susceptibility to brain injury or impaired repair mechanisms in subjects with ApoE-epsilon4.

Aged↗

PubMed1998

Quantification of elastic resistance knee rehabilitation exercises.

Elastic resistance exercises are frequently used for knee rehabilitation following injury and/or surgery. The evidence supporting this mode of rehabilitation is primarily anecdotal, and no biomechanical assessment of elastic resistance exercises has been previously published. The purpose of this project was to quantify muscle activation levels, knee joint angles, and applied force during five rehabilitation exercises utilizing an elastic resistance device. Twelve subjects with no previous knee injury performed double knee dip, hamstring pull, leg press, single knee dip, and side-to-side jump exercises while sagittal plane kinematics, applied force from the elastic resistance device, and electromyographic activity of eight lower extremity muscles were collected. The muscle activation patterns suggest a progressive continuum of rehabilitation exercises that can be applied to nonoperative injuries as well as anterior cruciate ligament reconstructions.

Adult↗

PubMed1994

Clinical and biochemical aspects of uric acid overproduction.

Purine nucleotides are synthesized and degraded through a regulated series of reactions which end in the formation of uric acid. Increased uric acid synthesis may be the result of two major pathophysiological disorders: increased de novo purine synthesis and enhanced purine nucleotide degradation, both of which may be the result of an increased or decreased enzyme activity. In addition, some conditions and disorders associated with uric acid overproduction have been recognized as the result of increased ATP degradation or decreased synthesis of ATP. The clinical manifestations of the diseases leading to excess uric acid synthesis are heterogenous, but symptoms related to uric acid overproduction are always secondary to the precipitation of crystals in soft tissues, joints, and the kidney excretory system. In clinical practice, serum urate concentration and urinary uric acid excretion are used to assess uric acid synthesis, taking into account that a purine-rich diet can be a confounding variable. Quantification of uric acid precursors, such as adenosine, inosine, guanosine, hypoxanthine, and xanthine, in biological fluids and intracellular nucleotides has provided further insight into the metabolic disturbances underlying disorders associated with uric acid overproduction. Additional studies are necessary to define precisely the metabolic derangement in idiopathic uric acid overproduction and to assess fully the consequences of increased purine nucleotide degradation, such as free-radical formation, increased adenosine synthesis, and reduced synthesis of signal transducers.

Adenosine Triphosphate↗

PubMed2002

Biological monitoring of aromatic diisocyanates in workers exposed to thermal degradation products of polyurethanes.

Exposure to diisocyanates was assessed by biological monitoring among workers exposed to the thermal degradation products of polyurethanes (PURs) in five PUR-processing environments. The processes included grinding and welding in car repair shops, milling and turning of PUR-coated metal cylinders, injection moulding of thermoplastic PUR, welding and cutting of PUR-insulated district heating pipes during installation and joint welding, and heat-flexing of PUR floor covering. Isocyanate-derived amines in acid-hydrolysed urine samples were analysed as perfluoroacylated derivatives by gas chromatography mass spectrometry in negative chemical ionisation mode. The limits of quantification (LOQs) for the aromatic diamines 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA) and 4,4'-methylenedianiline (4,4'-MDA) were 0.25 nmol l(-1), 0.25 nmol l(-1) and 0.15 nmol l(-1), respectively. The LOQ for the aliphatic diamines hexamethylenediamine (HDA), isophoronediamine (IpDA) and 4,4'-diaminodicyclohexyl methane (4,4'-DDHM) was 5 nmol l(-1). TDA and MDA were detected in urine samples from workers in car repair shops and MDA in samples from workers welding district heating pipes. The 2,4-TDA isomer accounted for about 80% of the total TDA detected. No 2.6-TDA was found in the urine of non-exposed workers. The highest measured urinary TDA and MDA concentrations were 0.79 nmol mmol(-1) creatinine and 3.1 nmol mmol(-1) creatinine, respectively. The concentrations found among non-exposed workers were 0.08 nmol mmol(-1) creatinine for TDA and 0.05 nmol mmol(-1) creatinine for MDA (arithmetic means). Exposure to diisocyanates originating from the thermal degradation of PURs are often intermittent and of short duration. Nevertheless, exposure to aromatic diisocyanates can be identified by monitoring diisocyanate-derived amines in acid-hydrolysed urine samples.

Adult↗

PubMed1990

Peptide containing nerves in human synovium: immunohistochemical evidence for decreased innervation in rheumatoid arthritis.

The innervation of normal and rheumatoid human synovium was studied by immunofluorescence microscopy. Antibodies against the general neuronal marker protein gene product (PGP) 9.5 and specific neuropeptides were used. We observed sensory nerves containing substance P (SP) and calcitonin gene related peptide (CGRP) as well as autonomic sympathetic fibers immunoreactive for neuropeptide tyrosine (NPY), its C terminal peptide (C-PON) and the catecholamine synthesizing enzyme tyrosine hydroxylase (TH). Three subpopulations of nerve fibers labelled with SP and CGRP were identified: some stained for SP or CGRP only and others contained both peptides. NPY/C-PON and TH labelled predominantly perivascular nerves. Quantification of immunostained nerves revealed a significantly decreased innervation of rheumatoid synovia. The densities of both PGP 9.5 and neuropeptide containing nerves were lower in all rheumatoid samples. Our results are compatible with a local release of neuropeptides into joint fluid and point to a disturbed neuronal control of rheumatoid synovial tissue.

Adolescent↗

PubMed1998

Quantitative assessment of temporomandibular joint disk status.

The purpose of this study was to quantify temporomandibular joint disk-slice information produced by magnetic resonance imaging by means of a stepwise discriminant analysis. One hundred ninety-four adolescents consented to magnetic resonance imaging evaluation of their temporomandibular joints. Sagittal magnetic resonance imaging slices of each joint were assigned to one of six subjective categories of disk position by an experienced maxillofacial radiologist. Standardized reference planes transferred to each magnetic resonance image from corresponding lateral cephalometric radiographics facilitated the measurement of disk length and disk displacement and the computation of ratio values of these measurements. Discriminant analysis revealed that all three quantitative variables were descriptive and discriminant for grouping slice data into pre-established subjective categories. Cross-validation and misclassification error calculations showed a 69.3% agreement between subjective and discriminant classification. Therefore quantification of disk displacement can be used in place of subjective evaluation. In addition, discriminant analysis disclosed a reduction in disk length associated with increased severity of disk displacement.

Adolescent↗

PubMed1995

Mathematical parameters for quantification of mutational responses in bacteria.

This paper introduces a new parameter, derivable from dose-response data for induced mutagenesis in bacteria, that can be used to quantify mutational responses in short-term tests. We called this parameter the mutational response of the bipartite experimental system (agent plus cells). We defined it as being jointly proportional to the efficiency of the mutagen and the sensitivity of the test. We show how this quantity can be used to rank order chemical carcinogens on the basis of their mutagenicity and to determine the strength of any quantitative correlation that may exist between mutagenicity in bacteria and carcinogenicity in rodents. We find that this particular measure of mutational response for 10 direct-acting monofunctional alkylating agents correlates remarkably well with the rodent carcinogenicity of these chemicals measured in terms of their reciprocal TD50 values.

Alkylating Agents↗

PubMed2000

Quantification of the cell infiltrate in synovial tissue by digital image analysis.

OBJECTIVE: The experience with digital image analysis (DIA) in the assessment of synovial inflammation is limited. In this study we compared DIA with two currently applied methods for the evaluation of the synovium. METHODS: Synovial tissue (ST) specimens were obtained by arthroscopy from knee joints of rheumatoid arthritis (RA) patients with variable disease expression and in control subjects. CD68+ macrophages and CD3+ T-cells were detected by immunohistochemical staining using two different labelling techniques. The labelled ST sections were quantified using three different analysis techniques: manual cell counting (MC), semi-quantitative analysis (SQA) and DIA. RESULTS: We observed strongly positive correlations between the three methods when examining T-cell infiltration: between MC and SQA: sigma=0.91 (P<0. 0001), between MC and DIA: sigma=0.95 (P<0.0001), and between SQA and DIA: sigma=0.83 (P<0.0001). Similarly, for the analysis of synovial intimal macrophages, positive correlations were noted between MC and SQA (sigma=0.62; P=0.002), MC and DIA (sigma=0.56; P<0.01), and SQA and DIA (sigma=0.79; P<0.0001). Finally, the analysis of synovial sublining macrophages revealed positive correlations between MC and SQA (sigma=0.95; P<0.0001), MC and DIA (sigma=0.64; P=0.001) and SQA and DIA (sigma=0.69; P<0.0001). CONCLUSION: These three different methods generated similar results. DIA offers the opportunity of a reliable and time-efficient analysis of the synovial infiltrate.

Aged↗

PubMed1988

Pain measurement in reflex sympathetic dystrophy syndrome.

The reflex sympathetic dystrophy syndrome (RSDS) consists of a triad of pain, edema and sympathetic dysfunction of an extremity following trauma, peripheral nerve injury or central nervous system disorder. Reflex sympathetic dystrophy syndrome is a difficult and costly pain syndrome to treat. One of the difficulties in evaluating treatment efficacy is the objectification and quantification of patient findings. The purpose of this investigation was to develop a simple, reproducible and systematic evaluation of pain and neurologic impairment in RSDS. The protocol evaluation included the following measures of pain and impairment: (1) objectification of distal joint pain by palpation (0-4 scale); (2) volumetric measurement by water displacement of the distal limb; (3) skin temperature measurement; (4) active range of motion assessment of the affected limb (AROM); (5) McGill Pain Questionnaire (MPQ); and (6) visual analogue pain scale (VAS). Seventeen subjects with definite or probable RSDS were evaluated. The mean age of patients was 35.6 years +/- 8.0 years (+/- 2 S.E.M.), and the mean duration of symptoms was 11.8 +/- 4.8 months. There were an equal number of subjects with upper and lower extremity involvement. The VAS had significant correlations with limb volume, AROM-lower extremity and joint pain indices (P less than 0.0005). The MPQ subscales had robust correlation with the joint pain indices alone (P less than 0.0001). Skin temperature was not predictive of changes in joint pain score, AROM, limb volume or subjective pain measures. However, there was internal consistency between volumetric and AROM measures and joint pain indices. This protocol is recommended for use in therapeutic trials for the treatment of the RSDS.

Adult↗

PubMed2006

Subadditive withdrawal from cocaine/kappa-opioid agonist combinations in Planaria.

We have previously developed and extensively characterized a convenient and sensitive metric for the quantification of withdrawal responses using Planaria. Planaria are particularly valuable for these studies because of their permeable exteriors and their relevant neurotransmitter systems (e.g., dopaminergic, opioid, and serotonergic). In the present study, we used this metric and mathematically rigorous joint-action analysis to investigate poly-drug withdrawal from fixed-ratio cocaine/kappa-opioid agonist combinations. The D50 (concentration producing half-maximal effect) for cocaine and U-50,488H was 10.3 and 1.02 microg, respectively. The D50 for 19:1 or 1:19 combinations did not differ significantly (p>0.05) from expected additive values (11.6+/-3.0 vs. 9.9+/-1.4 and 1.1+/-0.2 vs. 1.5+/-0.1, respectively), but the 3:1, 1:1, and 1:3 ratios did (34.5+/-6.9 vs. 7.7+/-1.1; 55.1+/-10.0 vs. 5.7+/-0.7; and 40.8+/-8.9 vs. 3.3+/-0.4, respectively), indicating subadditive interaction at these ratios. The finding of subadditivity in this model suggests that abstinence-induced withdrawal from the combination is less intense than that predicted from the individual drug potencies. The concept that certain combinations of drugs leads to attenuated withdrawal might generalize to humans.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

PubMed1989

Biomechanical analysis and assessment of lumbar stress during load lifting using a dynamic 19-segment human model.

A dynamic biomechanical human model is presented which allows the quantification of mechanical parameters such as torque, compressive and shear forces, and pressure at the lumbar intervertebral discs. The human model comprises a total of 19 body segments. Various trunk flexions can be analysed due to the provision of 5 joints at the level of the 5 lumbar intervertebral discs. The influence of intraabdominal pressure on spinal load is considered. The inclusion of the influences of gravity and inertia permits the analysis of both static body postures and dynamic body movements. Since the model is 3-dimensional, the lumbar stress can be calculated during both symmetrical tasks in the median sagittal plane as well as during non-symmetrical ones. The influences on spinal stress of trunk inclination and the position of an external load relative to the body are quantified for various load weights up to 50 kg. The torque at the lumbo-sacral joint L5-S1 lies, dependent on posture and load lever-arm, within the range between 0 and 500 Nm; the compressive force on L5-S1 lies within the range between 0.4 and 10 kN, and the shear force at L5-S1 between 0.2 and 0.9 kN. The influences of lift velocity and jerky movement on lumbar stress are quantified. Simulated humpback and hollow-back postures are studied. The compressive forces at the 5 lumbar intervertebral discs are compared. The validity of the model is examined by comparing the model calculations with the intradiscal pressure measurements taken from the literature. Strength tests on lumbar intervertebral discs and vertebrae are collated from the literature in order to assess the lumbar stress during load lifting. The lumbar ultimate compression strength varies within a wide range. The mean value for a total of 307 lumbar segments amounts to 4.4 kN, the standard deviation to 1.9 kN. In conclusion, lumbar compressive force values during lifting fall within the same range as the strength values for the human lumbar spine.

Biomechanical Phenomena↗

PubMed1999

Synovial fluid sampling from the temporomandibular joint: sample quality criteria and levels of interleukin-1 beta and serotonin.

The aims of this study were to compare two sets of quality criteria (SQC A and B) with respect to synovial fluid (SF) sampling and to present temporomandibular joint (TMJ) SF levels of IL-1 beta and 5-HT. The study comprised 310 TMJ SF samples from 12 healthy individuals (HI) and 59 patients with TMJ inflammatory disorders. Ten HI and 37 patients were selected for investigation of TMJ SF levels and samples were obtained by a push-and-pull method with quantification by vitamin B12. The SQC comprised aspirate weight (AW), dilution factor (DF), blood contamination and hemolysis. IL-1 beta and 5-HT levels did not differ between the samples that satisfied SQC A or B. The proportion of samples that satisfied SQC A was higher than for SQC B. Patients with polyarthritides had significantly higher TMJ SF concentrations of 5-HT and IL-1 beta than HL. In conclusion, there is a recovery of TMJ SF of 0.1-0.2 g with the method used and the criteria set with the highest success rate do not differ from the other one with respect to SF levels of IL-1 beta and 5-HT. This set of sample quality criteria comprised no hemolysis, no or only minor blood contamination, AW > 0.5 g and DF < 0.98. The higher SF levels in the diseased TMJ (polyarthritides) compared to the healthy joint with respect to 5-HT and IL-1 beta is of clinical diagnostic relevance and the presence of 5-HT or IL-1 beta in TMJ SF seems to indicate a pathological joint condition probably of an inflammatory nature.

Adolescent↗

PubMed1993

Articular cartilage echography as a criterion of the evolution of osteoarthritis of the knee.

We propose a modification of the Aisen's technique by which precise reproducible measurements of articular cartilage thickness of the knee is possible. A group of 23 patients with severe osteoarthritis was studied by ultra-sound (US) before knee prosthesis surgery. Evaluation with US was performed by a real-time scanner with a 7.5 MHz linear probe with upper-patellar transverse scans tangent to the upper patellar pole at 90 degrees knee flexion. The cartilage thickness was measured within the weight-bearing area. After surgery, on the corresponding gross pathological specimen, US re-evaluation and histological measurements were made. Results of pre- and post-operative ultrasonography (US) data were compared with histological data and a good correlation between these measurements was found (p(t) > 10%). Preoperative measurements ranged from 2.4 to 0.3 mm. In order to obtain normal reference values of the articular cartilage within the weight-bearing area of the femoral trochlea for comparison, a group of 10 control subjects was also studied with US as above. The US data were then compared with computed tomography (arthro-CT) evaluations. No significant differences in mean values were found between the two imaging techniques (2.2 mm versus 2.3 mm for the lateral condyle and 2.3 versus 2.3 for the medial condyle, respectively). We conclude that ultra-sound measurement of articular cartilage thickness of femoral condyles is a sensitive and reproducible technique which permits early diagnosis and management of knee arthropathy and also quantification of cartilage damage.

Adolescent↗

PubMed1987

Quantification of keratan sulfate in blood as a marker of cartilage catabolism.

Concentrations of circulating cartilage-derived keratan sulfate (KS) are significantly higher in patients with osteoarthritis (OA) than in adults without cartilage disease. The increases in serum KS levels in the OA group are likely the result, at least in part, of cartilage degradation in affected joints. If the appearance of elevated levels of serum KS do indeed correlate with the extent of cartilage erosion or destruction in individuals with OA, measurements of serum KS levels will prove extremely useful in the assessment and diagnosis of this joint disease.

Adult↗

PubMed2004

Radiological progression of joint damage in a longitudinal cohort of early DMARD-treated rheumatoid arthritis patients followed for 10 years.

OBJECTIVE: The efficacy of DMARD therapy in rheumatoid arthritis (RA) can be judged by radiological analysis. This study aimed to determine the time-dependent progression of joint damage, acute-phase response, and rates of radiologic progression in early DMARD-treated RA patients over 10 years. PATIENTS AND METHODS: We evaluated outpatient records, and radiographs of hands and feet of 54 early RA patients on DMARDs for 10 years. Radiographs were quantified by the Larsen method using recently developed quantification software. RESULTS: Radiological damage attenuated, with disease progression from baseline to Year 10 [correlation coefficient (r)=0.95, probability (p)<0.001]. Radiographic scores progressed more rapidly during the first 5 years than thereafter. Cumulative erythrocyte sedimentation rate (ESR) was strongly correlated with radiological progression (p<0.001, r=0.88). CONCLUSION: Our findings reveal a higher amount of radiographic RA progression during the first years of DMARD treatment. Thus, our data provide strong evidence for the importance of both early DMARD therapy and continuous radiographic assessments in RA.

Adult↗

PubMed2004

In vitro low-speed side collisions cause injury to the lower cervical spine but do not damage alar ligaments.

Whether injuries to the alar ligaments could be responsible for complaints of patients having whiplash injury in the upper cervical spine is still controversially discussed. It is known that these ligaments protect the upper cervical spine against excessive lateral bending and axial rotation movements. The objective of the present in vitro study was therefore to examine whether the alar ligaments or any other structures of the cervical spine are damaged in side collisions. In a specially designed acceleration apparatus, six human osteoligamentous cervical spine specimens were subjected to incremental 90 degrees side collisions from the right (1 g, 2 g, 3 g, etc.) until structural failure occurred. A damped pivot table accounted for the passive movements of the trunk during collision, and a dummy head (4.5 kg) ensured almost physiological loading of the specimens. For quantification of functional injuries, the three-dimensional flexibility of the specimens was tested in a spine tester before and after each acceleration. In all six specimens, structural failure always occurred in the lower cervical spine and always affected the facet joint capsules and the intervertebral discs. In four specimens, this damage occurred during the 2 g collision, while in the other two it occurred during the 3 g and 4 g collision, respectively. The flexibility mainly increased in the lower cervical spine (especially in lateral bending to both sides) and, to a minor extent, in axial rotation. In vitro low-speed side collisions caused functional and structural injury to discoligamentous structures of the lower cervical spine, but did not damage the alar ligaments. Since the effects of muscle forces were not taken into account, the present in vitro study reflects a worst-case scenario. Injury thresholds should therefore not be transferred to reality.

Acceleration↗

PubMed2006

No difference in early cellular response of the pseudo-synovial membrane after total hip arthroplasty: comparison of 3 combinations of bearing materials.

BACKGROUND: Wear-resistant bearing materials may hypothetically reduce chronic inflammation in the pseudosynovial membrane as compared to less wear-resistant bearing materials such as polyethylene. We assessed the foreign body response in the pseudosynovial membrane in vivo after total hip replacement. METHODS: 37 patients from a larger prospective randomized trial of 225 patients had biopsies taken arthroscopically from the artificial hip joint (i.e. the pseudosynovial membrane) 1 year after insertion of the implant. All patients had an identical hip prosthesis (Bimetric-RingLoc) except for the bearing materials, which consisted of polyethylene on zirconia, CoCr on CoCr, or alumina on alumina. Histological quantification was performed on 2-mum-thick semi-thin plastic sections or paraffin sections by point counting technique to compare the volume fraction of macrophages, granulomas and endothelial cells in biopsies of the pseudosynovial membrane. RESULTS: The median macrophage volume fractions for polyethylene-on-zirconia bearing material (n = 15), CoCr-on-CoCr (n = 9), and alumina-on-alumina (n = 11) were 0.02, 0.04, and 0.004, respectively. The median granuloma volume fractions for polyethylene-on-zirconia (n = 13), CoCr-on-CoCr (n = 9), and alumina-on-alumina (n = 13) were 0.02, 0.04, and 0.02, respectively. The median endothelial cell volume fractions for polyethylene-on-zirconia (n = 15), CoCr-on-CoCr (n = 9), and alumina-on-alumina (n = 11) were 0.03, 0.02, and 0.05, respectively. Statistical analysis showed no significant differences between the three groups with the different bearings with respect to volume fraction of macrophages, granulomas and endothelial cells. INTERPRETATION: Our study demonstrated that a granulomatous inflammation is a common finding in non-loose implants as early as 1 year after the operation not demonstrating a difference in macrophages and granuloma formation with the various bearing materials. Thus a high volume fraction of macrophages was found in the osteoarthritis control group compared to the operated group.

Adult↗

PubMed1997

Ultrastructure of the synovial sensory peptidergic fibers is distinctively altered in different phases of adjuvant induced arthritis in rats: ultramorphological characterization combined with morphometric and immunohistochemical study for substance P, calcitonin gene related peptide, and protein gene product 9.5.

OBJECTIVE: To characterize sequential ultramorphological changes in synovial sensory peptidergic fibers in different phases of adjuvant induced arthritis. METHODS: Topographically defined regions of the tarsal joints from arthritic rats were evaluated 7, 10, 14, and 21 days after inoculation with Freund's adjuvant. Peptidergic fibers were identified by high resolution video microscope, then fibers containing calcitonin gene related peptide (CGRP) were visualized by electron microscopy. Morphometric quantification of synovial fibers immunohistochemically stained for CGRP, substance P (SP), and protein gene product 9.5 (PGP 9.5) was done at this time. RESULTS: The control synovial lining contained numerous ramified axon terminals, whereas the sublining contained mostly nerve fiber bundles, except for axon terminals visible around the blood vessels. In arthritis, on Day 14, there were few immunoreactive nerve fibers and terminals. Instead, electron microscopy disclosed numerous activated and/or degenerated axons [CGRP: 2973 +/- 345 vs 495 +/- 288; SP: 657 +/- 344 vs 199 +/- 60; PGP 9.5: 4473 +/- 944 vs 886 +/- 299, all p < 0.05 (units: microm/mm2)]. On Day 21 CGRP and PGP 9.5 immunoreactive fibers were numerous again (4892 +/- 551 and 3613 +/- 1350, respectively), but SP immunoreactive nerve fibers did not seem to regenerate (126 +/- 44). Regenerating nerve fibers had a distinctive ultrastructure and they were always seen in association to Schwann cells. CONCLUSION: The healthy synovial lining is innervated by peptidergic nerve terminals. During the inflammatory phase of arthritis neuropeptides are locally released due to stimulation and degeneration of the axons. The apparently unaffected Schwann cells seem to play a pivotal role in subsequent regeneration of peptidergic axons. However, the ultrastructure and the neuropeptide content (and probably the function) of the regenerating axons are different from those of the normal synovial nerve fibers.

Animals↗