Measurement of bone mineral density at the spine and proximal femur by volumetric quantitative computed tomography and dual-energy X-ray absorptiometry in elderly women with and without vertebral fractures.

The goal of this study was to determine the effect of vertebral fracture status on trabecular bone mineral density (BMD) measurements obtained in the proximal femur and spine by helical volumetric quantitative computed tomography (vQCT). The study population consisted of 71 Italian women (average age 73 +/- 6) years. This group included 26 subjects with radiographically confirmed atraumatic vertebral fractures and 45 controls. The subjects received helical CT scans of the L1 and L2 vertebral bodies and the hip. The three-dimensional CT images were processed using specialized image analysis algorithms to extract measurements of trabecular, cortical, and integral BMD in the spine and hip. To compare the vQCT results with the most widely used clinical BMD measurement, dual X-ray absorptiometry (DXA) scans of the anteroposterior (AP) spine and proximal femur were also obtained. The difference between the subjects with vertebral fractures and the age-matched controls was computed for each BMD measure. All BMD measurements showed statistically significant differences, which ranged from 7% to 22% between subjects with fractures and controls. Although, given our small sample size, we could not detect statistically significant differences in discriminatory power between BMD techniques, integral BMD of the spine measured by vQCT and DXA tended to show stronger associations with fracture status (0.001 < p < 0.004). Measurements by QCT and DXA at the hip were also associated with vertebral fracture status, although the association of DXA BMD with fracture status was explained largely by differences in body weight between subjects with vertebral fractures and controls.

The lumbar spine: imaging in rheumatic disease.

Seronegative inflammatory spondyloarthropathies include ankylosing spondylitis, psoriatic arthritis, Reiter syndrome, juvenile chronic arthritis and colitic arthritis. These diseases share some characteristics among which the most important is the presence of the histocompatibility antigen HLA B27; moreover the frequent overlapping of the various inflammation patterns have accounted for their classification in a single group. Diagnostic imaging can differentiate among the different forms only if the diagnostic algorithm, based on clinical history and laboratory findings is followed, considering the advantages and limitations of each method. In this respect, it should be kept in mind that the findings relative to the spine and sacroiliac joints allow to establish a definitive diagnosis.

Imaging in degenerative disease of the lumbar spine.

Degenerative disease involves all spinal components. Conventional radiology and digital radiology are the procedures of first choice in order to establish the diagnosis. CT and MRI should be considered of second choice, based on precise indications. The physiologic aspects of the spine during aging are differentiated from the degenerative alterations and relative complications specific of arthrosis with modern available imaging procedures.

Imaging of sacroiliac joints.

The early diagnosis of inflammatory and degenerative disease of sacroiliac joints is markedly difficult because the clinical pattern is not dissimilar from that of diseases involving the lumbar spine and sciatic nerve. Furthermore as in inflammations in general, when only structural changes in the synovial membrane and cartilage are involved, the findings of conventional radiology are often nondiagnostic. CT is now considered the gold standard procedure because in spite of its nonnegligible limitations, single lesions in the synovial and ligamentous compartments can be distinctively evidenced. MRI, unlike other procedures, affords the early nonspecific documentation of intrinsic and/or reactive alterations in the subchondral bone, therefore it appears to fill the gap between the onset of symptoms and the imaging visualization of sacroiliitis.

Combined imaging in spondylodiscitis.

At present, in spite of the advancement in antibiotic therapy no significant decrease in the incidence of spinal infections is observed: most likely, this is correlated to the increased immigration flows, high risk behaviors (drug addiction, alcoholism), immunosuppressive diseases (AIDS, leukemia, lymphoma), interventional procedures (iatrogenic causes). Early diagnosis, at times difficult and often misunderstood, is facilitated by the use of a correct diagnostic algorithm, supported by blood culture, needle aspiration and biopsy. Aim of this report was to evaluate the role of the different imaging procedures, CT and MRI in particular, for prompt correct therapeutic management.

Age-related changes assessed by peripheral QCT in healthy Italian women.

The purpose of this study was to describe the normal cross-sectional pattern of radial bone loss associated with aging in healthy women and to generate a normative database using peripheral quantitative computed tomography (pQCT). Subjects with suspected conditions affecting bone metabolism or receiving any drugs affecting bone mineralization were excluded. The trabecular bone mineral density (BMD) and the total bone density of the ultradistal radius at the nondominant forearm was measured using the Norland-Stratec XCT-960 pQCT scanner in 386 healthy pre-, peri-, and postmenopausal females aged 15-81 years. The long-term in vivo precision error was 1.6 % CV (coefficient of variation) for trabecular and 0.8% CV for total BMD measurements. The highest value of trabecular and total BMD measured was observed at the age group 15-39 years. Beyond these ages both trabecular and total BMD showed a linear decline with aging, decreasing by an overall slope of -1.28 and -0.55 mg/cm3 per year for total and trabecular BMD measurements, respectively. The test of parallelism between the regression slopes of the peri- and postmenopausal women showed a statistically significant difference for total BMD measurement (p = 0.003). Measurement of total and trabecular BMD was not influenced by weight, height or body mass index, but it was correlated with natural logarithm of years since menopause. We conclude that pQCT of the ultradistal radius is a precise method for measuring the true volumetric BMD and for detecting age-related bone loss in the trabecular and total bone of female subjects encompassing the adult age range and menopausal status.

Phalangeal US velocity discriminates between normal and vertebrally fractured subjects.

The purpose of this study was to evaluate the diagnostic sensitivity of phalangeal bone ultrasound velocity of the hand in the diagnosis of osteoporosis and to compare this technique to bone mineral density (BMD) measurement at the lumbar spine assessed by dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). We investigated US velocity at the distal metaphysis of the proximal phalanx and spinal BMD in 101 women. Fifty-nine were healthy (mean age 50 +/- 11.6 years) and 42 were osteoporotic (mean age 65 +/- 6.6 years) with documented vertebral fractures. In the healthy population the relation with age was, respectively, r = -0.73 (p < 0. 0001) for quantitative US (QUS), r = -0.74 (p < 0.0001) for QCT and r = -0.48 (p < 0.01) for DXA. Both US and DXA were correlated with QCT: r = 0.74 and r = 0.77 (p < 0.0001), respectively. Correlation of QUS and DXA was r = 0.56 (p < 0.0001). Phalangeal US velocity and spinal BMD (QCT and DXA) values discriminate healthy from osteoporotic women. Age-adjusted logistic regression analysis of the data showed standardized odds ratios (OR) for vertebral fracture to be similar for US and DXA (OR = 1.8 and 1.5, respectively) and stronger for QCT (OR = 2.9). Phalangeal US velocity reflects age-related bone loss and differentiates between healthy and osteoporotic subjects.

Diffuse idiopathic skeletal hyperostosis.

OBJECTIVE: To describe the axial and appendicular skeleton findings of diffuse idiopathic skeletal hyperostosis. To analyze the role of conventional radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of this condition. To discuss the differential diagnosis and diagnostic pitfalls of this disease. MATERIAL AND METHODS: The involvement of vertebral and extravertebral sites including the pelvis, calcaneum, ulnar olecranon, and patella is frequently found in the literature. The lesions described are the anterior and lateral ossification of the spine, hyperostosis at sites of tendon and ligament insertion, ligamentous ossification, and periarticular osteophytes. The criteria for the diagnosis of diffuse idiopathic skeletal hyperostosis involving the spine are: flowing ossification along the anterior and anterolateral aspects of at least four contiguous vertebrae, preserved intervertebral disc height, no bony ankylosis of the posterior spinal facet joints, and finally no erosion, sclerosis or bony ankylosis of the sacroiliac joints. RESULTS: The disease has about the same frequency in men (65%) and women (35%); it is most common in the thoracic spine and occurs less frequently in the lumbar and cervical spine. The disease most commonly presents in the sixth and seventh decades of life and its estimated frequency in the elderly is 5-15%. Signs and symptoms include stiffness and pain in the back, dysphagia due to direct esophageal compression/distorsion, pain related to associated tendinitis, myelopathy related to core compression associated to the ossification of the posterior longitudinal ligament, and pain related to vertebral complications--e.g. fracture/subluxation. CONCLUSION: While conventional radiography clearly confirms the diagnosis of diffuse idiopathic skeletal hyperostosis, CT and MRI better detect associated findings (e.g. ossification of the posterior longitudinal ligament) and complications (e.g. spinal cord compressive myelomalacia).

Ultrasonography versus computed tomography in evaluation of the femoral trochlear groove morphology: a pilot study on healthy, young volunteers.

The aim of the study was to verify the efficacy of ultrasonography (US) in evaluating the morphology of normal trochlea, especially the sulcus angle and the trochlear depth, in comparison with computed tomography (CT) (gold standard). The knees of 11 asymptomatic volunteers were subjected to US and CT evaluation of the same section planes and the results were compared. For statistical evaluation Spearman's correlation coefficient analysis was used. A statistically significant correlation was found between the two diagnostic procedures (sulcus angle: r = 0.820; trochlear depth: r = 0.802; Spearman's correlation coefficient) and the intra-observer variability for the US measurements (sulcus angle: r = 0.966; trochlear depth: r = 0.914; Spearman's correlation coefficient). The mean value of sulcus angle and trochlear depth was 132 degrees and 5.6 mm, respectively, similar to those reported in the literature. We conclude that evaluation by US of both sulcus angle and trochlear depth is as reproducible and sensitive as that performed with CT.

Long-term in vitro precision of single slice peripheral Quantitative Computed Tomography (pQCT): multicenter comparison.

In a multicenter evaluation the precision and stability of single slice peripheral Quantitative Computed Tomography (pQCT) systems were assessed. Compared to central Europe the peripheral QCT device is also widely used in the Italian health care system. Phantoms were measured frequently on each machine in four pQCT scanners over a two-year period using an identical automated software program. Intrasite and intersite phantom mineral densities, expressed in units of mg/cm3, were analyzed and examined. The short and long term precision were estimated from the consistency of these measurements using the root mean square error and expressed as coefficient of variation in percent (% CV). Short term precision was good (mean intrasite coefficient of variation (CV) 0.21 +/- 0.056 standard deviation (SD)). Intersite measurements of a single phantom revealed differences between machines of the same type of not more than 2.9 mg/cm3. At four sites frequent phantom measurements revealed a mean CV of 0.18% (range 0.12-0.28). No significant changes in the regression slopes (drift of the machine versus time) were observed. We conclude that the in vitro precision and stability of the single slice pQCT systems are sufficiently high and unlikely to negatively affect the in vivo precision.

In vitro binding of ciliary neurotrophic factor to its receptors: evidence for the formation of an IL-6-type hexameric complex.

Ciliary neurotrophic factor (CNTF) is a cytokine sharing structural and functional similarities with interleukin-6 (IL-6) and other helical cytokines that utilize the common signalling chain gp130. While IL-6 induces gp130 dimerization, CNTF, after the initial interaction with the specific, non-signalling receptor subunit, CNTFR, induces the formation of gp130/LIF-receptor heterodimers. Through immunoprecipitation experiments with tagged soluble receptor molecules, we recently demonstrated that IL-6 drives the formation of a hexameric receptor complex with a defined topology and composed of two IL-6, two IL-6R alpha and two gp130 molecules. Here, we apply the same strategy to study the assembly in vitro of the CNTF receptor complex. We present evidence that both the cytokine and the specific binding chain undergo dimerization in the presence of gp130. Furthermore, although gp130 and LIFR are able to bind independently to the CNTF/CNTFR sub-complex, they never form homodimers but only heterodimers. We propose that CNTF assembles a hexameric receptor complex composed of two CNTF, two CNTFR, one gp130 and one LIFR molecule, and present a model of the reciprocal interaction of these molecules based on similarities with the IL-6 hexameric complex.

Two distinct and independent sites on IL-6 trigger gp 130 dimer formation and signalling.

The helical cytokine interleukin (IL) 6 and its specific binding subunit IL-6R alpha form a 1:1 complex which, by promoting homodimerization of the signalling subunit gp130 on the surface of target cells, triggers intracellular responses. We expressed differently tagged forms of gp130 and used them in solution-phase binding assays to show that the soluble extracellular domains of gp130 undergo dimerization in the absence of membranes. In vitro receptor assembly reactions were also performed in the presence of two sets of IL-6 variants carrying amino acid substitutions in two distinct areas of the cytokine surface (site 2, comprising exposed residues in the A and C helices, and site 3, in the terminal part of the CD loop). The binding affinity to IL-6R alpha of these variants is normal but their biological activity is poor or absent. We demonstrate here that both the site 2 and site 3 IL-6 variants complexed with IL-6R alpha bind a single gp130 molecule but are unable to dimerize it, whereas the combined site 2/3 variants lose the ability to interact with gp130. The binding properties of these variants in vitro, and the result of using a neutralizing monoclonal antibody directed against site 3, lead to the conclusion that gp130 dimer is formed through direct binding at two independent and differently oriented sites on IL-6. Immunoprecipitation experiments further reveal that the fully assembled receptor complex is composed of two IL-6, two IL-6R alpha and two gp130 molecules. We propose here a model representing the IL-6 receptor complex as hexameric, which might be common to other helical cytokines.

[The sulcus angle of the femoral trochlea: ultrasonographic evaluation]. / Angolo del solco della troclea femorale. Valutazione ecografica.

The sulcus angle of femoral trochlea is particularly important to evaluate the femoro-patellar joint. Our study was aimed at studying the normal trochlea, and especially the sulcus angle, with US. The right knees of 11 normal subjects were examined with US and Computed Tomography (CT) on the same section planes. The US measurements of the sulcus angle were correlated with CT results, which were considered the gold standard. The US and CT data were compared and a direct correlation was found (r = 0.832). The intraobserver difference in US measurements was r = 0.943. The mean sulcus angle value was 132 degrees, in agreement with literature data. We conclude that the US measurements of the sulcus angle are reproducible and as sensitive as CT.

Nonradioactive receptor binding assay for ciliary neurotrophic factor.

A nonradioactive receptor binding assay for ciliary neurotrophic factor (CNTF) is described. The assay is based on the interaction between biotinylated human CNTF, soluble gp130, and soluble myc-tagged CNTF receptor captured on a microtiter plate via an antibody against the myc epitope tag. Bound cytokine is revealed by alkaline phosphatase-conjugated avidin. Purified human and rat CNTF competed with biotinylated CNTF for receptor binding, with IC50 values of 29 and 2 nM, respectively. Since the higher affinity of rat vs human CNTF has been previously shown to be conferred by the arginine residue at position 63 of the rat protein, we also tested a human CNTF mutant carrying a Q63R substitution. Secreted forms of wild-type and mutant CNTF were expressed in Escherichia coli, and the amount of cytokines in periplasmic extracts was determined by quantitative Western blotting analysis. The human CNTF mutant (Q63R, N137S) was found to compete with biotinylated CNTF for binding to soluble CNTF receptor with an eightfold higher apparent affinity than wild-type human CNTF. The present method thus faithfully reproduces the relative activities of CNTF analogs determined in other assay systems. The possibility of assaying cytokines in crude bacterial extracts makes the new technique particularly suitable for rapidly determining the receptor binding potencies of genetically engineered CNTF variants.

The effects of (+/-)-idazoxan and its stereoisomers on mouse vas deferens motility in vitro. A comparison with yohimbine.

The effects of idazoxan (IDZ) and its stereoisomers were compared to that of a classical alpha 2-antagonist, yohimbine (YOH), on para-aminoclonidine (PAC)- and norepinephrine (NE)-mediated inhibition of the twitch response evoked in the mouse vas deferens by low-frequency (0.1 Hz) field stimulation. (+/-)-IDZ and (+)-IDZ antagonized the inhibitory effects of PAC, (+)-IDZ being twice as potent as (+/-)-IDZ; in contrast, antagonism by (-)-IDZ failed to meet Schild criteria for a competitive mechanism. YOH completely reversed the inhibition of twitch response induced by NE, but not that induced by PAC; in the latter case, residual inhibition was almost fully reversed by (+)-IDZ and to a lesser extent by (+/-)-IDZ, while (-)-IDZ proved ineffective. These results provide pharmacological evidence of alpha 2-receptor heterogeneity at the vas deferens level. A possible additional mechanism involving imidazoline binding sites is discussed.

Multiple forms of synaptic coordinative interactions in the autonomic neurotransmission. Tensiometric evaluations in peripheral tissues.

The existence of co-transmitters interacting in the complex regulation of autonomic neurotransmission, has led to investigate the interactive effects between the conventional neurotransmitters and other drugs, such as histamine, serotonin, substance P, strictly related to inflammatory mediators, in both vas deferens and urinary bladder of guinea pig. The results suggest that synergistic interactions, involving post-synaptic sites, exist between co-transmitters; furthermore, inflammatory mediators are able to modify the responses to endogenous (via intramural nerves stimulation) and exogenous conventional neurotransmitters. It is conceivable that inflammatory mediators, released by activation of mast cells either within or delivered to the tissues by the vascular supply, may alter the physiological responses of several organ systems.

[Multiple receptor interactions in the electrically stimulated ductus deferens of the guinea-pig]. / Interazioni recettoriali multiple su dotto deferente elettrostimolato di cavia.

The evidence that ATP is released with noradrenaline as a cotransmitter from sympathetic nerve endings in the isolated guinea-pig vas deferens, had led to investigate the potential interactive effects of P2 and alpha 1 receptors, extending the observations to potentially synergistic interactions of histamine-, acetylcholine- and serotonin-receptors. Ineffective concentrations of histamine, carbachol and serotonin increase the neurogenic response to field stimulation; this effect is prevented by the specific antagonist. The responses to the exogenously applied ATP and noradrenaline are increased as well, suggesting that this synergistic interaction of carbachol is less specific. It can be envisaged that receptor complex is a multicomponent system with subunits specific for the primary neurotransmitter and accessory subunits which may interact to increase the responsiveness of the target cell to simultaneous afferent stimuli.

Pre-junctional regulation of sympathetic neurotransmission in the mouse vas deferens: assessment of agonist and antagonist potencies.

Dopaminergic agonists and antagonists were tested on the field-stimulated mouse vas deferens. Both LY 171555 and SK & F 38393, relatively selective DA2 and DA1 receptor agonists, respectively, produced concentration-dependent inhibition of the field stimulation-induced contractions, without modifying the baseline tone nor the contractile responses to the exogenous noradrenaline. Both LY 171555 and SK & F 38393 concentration-response curves were shifted rightward in a parallel manner by sulpiride (relatively specific DA2 antagonist) and SCH 23390 (relatively specific DA1 antagonist), respectively. The results are suggestive of the existence of pre-junctional dopamine receptors involved in the regulation of sympathetic neurotransmission in rodent vasa.

[Effects of the partial dopamine receptor agonist, terguride, on the field-stimulated vas deferens in the mouse]. / Effetti di un agonista dopaminergico parziale, terguride, sul dotto deferente elettrostimolato di topo.

Transdihydrolisuride (terguride), a 9,10-dihydrogenated analogue of the ergot dopamine agonist lisuride, is characterized as partial dopamine receptor agonist at CNS level. This compound was investigated for its effects on peripheral neurotransmission in the attempt to delineate its pharmacological profile. The contractile responses of field-stimulated mouse vas deferens were slightly inhibited by terguride at very high concentrations (10(-5)-10(-2) M); the selective antagonists for alpha 2-adrenergic and dopamine receptors failed to counteract this effect. Terguride was very effective in blocking the inhibitory effects of LY 171555 (selective DA2 agonist), SK&F 38393 (selective DA1 agonist) and clonidine (selective alpha 2 agonist). In no case the antagonism was competitive: the control dose-response curves were not shifted in a parallel and dose-dependent manner. Therefore terguride displays a mixed DA1, DA2 and alpha 2 antagonistic activity.