Symptoms of lumbar spinal stenosis in people with knee or hip osteoarthritis or low back pain: a cross-sectional study of 10,234 participants in primary care.

OBJECTIVE: The aims of this study were to evaluate: the proportion of people reporting symptoms associated with lumbar spinal stenosis (LSS) in primary care programs for knee or hip osteoarthritis (OA) or persistent low back pain (LBP) and; the prevalence of self-reported clinical LSS in these three cohorts, according to two sets of adapted criteria. METHOD: A cross-sectional analysis of baseline data from the Good Life with osteoArthritis in Denmark primary care programs. Self-report LSS symptom questions were administered to participants with knee OA, hip OA, and persistent LBP. The prevalence of eleven LSS symptoms and clinical LSS were calculated for each cohort. RESULTS: A total of 10,234 participants were included in the analysis. A similar proportion of participants in each cohort were female (69%), with a 6- and 7-year older mean age in the knee and hip cohorts compared to the back cohort. A greater proportion of participants with LBP reported LSS symptoms (range 11-71%) than in the hip (11-50%) and knee (8-40%) cohorts. This pattern was observed for all but one symptom. The same pattern was observed for the prevalence of clinical LSS with less than 10% of people in each cohort satisfying the clinical criteria. CONCLUSION: Self-reported LSS symptoms are commonly reported by people treated in primary care for knee or hip OA, although not as frequently as reported by those with LBP. Despite symptoms of LSS being common, only a small proportion of people were classified as having self-reported clinical LSS.

The diagnostic value of three sacroiliac joint pain provocation tests for sacroiliitis identified by magnetic resonance imaging.

OBJECTIVES: The aim of the current study was to investigate the diagnostic value of three sacroiliac (SI) joint pain provocation tests for sacroiliitis identified by magnetic resonance imaging (MRI) and stratified by gender. METHOD: Patients without clinical signs of nerve root compression were selected from a cohort of patients with persistent low back pain referred to an outpatient spine clinic. Data from Gaenslen's test, the thigh thrust test, and the long dorsal sacroilia ligament test and sacroiliitis identified by MRI were analysed. RESULTS: The median age of the 454 included patients was 33 (range 18-40) years and 241 (53%) were women. The prevalence of SI joints with sacroiliitis was 5%. In the whole study group, only the thigh trust test was associated with sacroiliitis, the area under the receiver operating characteristic (ROC) curve (AUC) was 0.58 [95% confidence interval (CI) 0.51-0.65], sensitivity 31% (95% CI 18-47), and specificity 85% (95% CI 82-87). In men, sacroiliitis was associated with all the SI joint tests assessed and multi-test regimens, with the greatest AUC found for at least one positive out of three tests [AUC 0.68 (95% CI 0.56-0.80), sensitivity 56% (95% CI 31-79), and specificity 81% (95% CI 77-85)]. In women, no significant associations were observed between the SI joint tests and sacroiliitis. CONCLUSIONS: Only in men were the SI joint tests found to be associated with sacroiliitis identified by MRI. Although, the diagnostic value was relatively low, the results indicate that the use of SI joint tests for sacroiliitis may be optimized by gender-separate analyses.

Vitamin A metabolism in rats chronically treated with 3,3',4,4',5,5'-hexabromobiphenyl.

Chronic dietary administration of 3,3',4,4',5,5'-hexabromobiphenyl (HBB), 1 mg/kg diet, caused a decrease in retinol (20-fold) and retinyl esters (23-fold) in the livers of female rats, but resulted in a 6.4-fold increase in retinol and 7.4-fold increase in retinyl esters in the kidneys. Liver acyl-CoA:retinol acyltransferase and retinyl palmitate hydrolase activities were reduced while serum concentration of retinol was unaffected by HBB feeding. Metabolism of a physiological dose of [11-3H]retinyl acetate (10 micrograms), was examined in rats fed either vitamin A-adequate diet, or marginal amounts of vitamin A, or vitamin A-adequate diet containing HBB. A 13-fold greater amount of the administered vitamin A was found in kidneys of HBB-treated rats. In rats fed adequate or low amounts of vitamin A, kidney radioactivity was primarily in the retinol fraction, while in HBB-fed rats the radioactivity was associated mostly with retinyl esters. Fecal and urinary excretion of radioactivity was greatly increased in HBB-treated rats. Chronic HBB feeding results in a loss of ability of liver to store vitamin A, and severely alters the uptake and metabolism of vitamin A in the kidneys. We conclude that HBB causes major disturbances in the regulation of vitamin A metabolism.

Effect of hexachlorobiphenyl on vitamin A homeostasis in the rat.

Vitamin A status and turnover were examined in rats that had been exposed to chronic dietary treatment of 3,4,5,3',4',5'-hexachlorobiphenyl (HCB), 1 mg/kg diet. HCB caused hepatic depletion and renal accumulation of vitamin A, and a 1.7-fold increase in the serum retinol concentration. Intravenously administered [3H]retinol bound to retinol binding protein-transthyretin complex (RBP-TTR complex) was used to study the dynamics of circulatory retinol in these rats. In HCB-treated rats, the plasma turnover rate of retinol was increased compared to vitamin A-adequate untreated controls. HCB caused a 50% reduction of total radioactivity in liver, and, except for 0.5 h after the [3H]retinol-RBP-TTR dose, the specific activity of the hepatic retinyl ester pool was greater compared to control rats. The kidneys of HCB-treated rats accumulated radioactivity in the retinyl ester fraction. HCB also caused a 50% reduction in adrenal radioactivity compared with control rats. Urinary and fecal excretion of radioactivity was 3-fold higher in HCB-treated rats as compared to controls. Our findings demonstrate that chronic HCB feeding results in expansion of plasma vitamin A mass, in changes of liver and kidney retinol and retinyl ester pool dynamics and in an increased metabolism of vitamin A.

The growth of children's moment of inertia.

As children grow, their moments of inertia increase. The magnitude and timing of these changes can affect the rotations of the body. The present study evaluated inter-individual differences in the transverse centroidal moment of inertia for 12 boys between 5 and 16 yr, using intra-individual data from three successive years. Segmental masses and moments of inertia were estimated using the elliptical zone model and the model then repositioned into two configurations: a layout position from a back handspring and a tuck position from a back somersault. In each case, the mass centroid and the moment of inertia about the transverse axis were calculated. With growth indexed by age, it was shown that the rate of change increases with age. For the children 10 yr and younger, the rate of change of moment of inertia was approximately 30% of the rate for the older children. Also, at each age level, there was a wide range of moments of inertia. In order to improve the prediction of moment of inertia, height and mass were tried as predictors with a noticeable improvement in correlation and linearity. The best predictor, however, was found to be the product of mass and height squared (M X H2) with correlations of 0.99 and 0.97. It is suggested that, because of the effects of growth on the moment of inertia. M X H2 could be used in conjunction with age in order to better appreciate the potential effects of change of moment of inertia.

The effect of a 12-month growth period on the body moments of inertia of children.

The effect of growth over a 12-month period on the principal moments of inertia for the body was investigated. The body was considered to be modelled as composed of elliptical zones 2 cm wide. Twelve children between the ages of 4 and 12 years and of different body types were tested and retested after 12 months. Moments of inertia for the three principal axes were calculated. A comparison of the results for the moment of inertia about the centroidal transverse axis showed increases from 12-57%. The results for the longitudinal centroidal axis ranged from 8-92%. For most of the children these percentage changes exceeded those in the traditional indicators of age, height, and mass. The product, mass times height squared (MH2), appeared to indicate the changes more accurately. Extreme changes were noted for a 12/13-year-old undergoing pubescent growth, a 6/7-year-old ectomorph, and a 4/5-year-old endomorph. It is suggested that the extreme changes, in particular, would make rotational movements difficult and there could be an extended adaptation period.

Growth of segment principal moments of inertia between four and twenty years.

Although there have been numerous studies of the moments of inertia of the body segments using a variety of the techniques, few have reported the principal moments and none has considered the changes in the principal moments during childhood and adolescence. The purpose of this study was to use a mathematical model to determine the intraindividual changes and interindividual differences in the segment principal moments during growth. The body was modelled as 15 segments and composed of transverse elliptical zones of known density. Moments and products of inertia about the segment mass centroid were calculated and the principal moments and axes determined from the ellipsoid of inertia. A mixed longitudinal study of 12 boys over 9 yr for a total of 88 annual recordings covering the age range 4 to 20 yr was conducted. Polynomial regressions fitted to the intraindividual changes showed a similarity in the curves to 10 yr followed by a wide divergence of growth patterns. The changes in the principal moments across age follow the principles of cephalocaudad and distal to proximal development for all three axes. These changes are more accentuated than the changes for segment length, volume, or mass. The results were consistent with principal moments reported for cadavers and young male adult gamma radiation scans as well as estimates based on simplified models of the segments. The magnitude of the changes in principal moments with age makes it essential that appropriate parameters be used in the analysis or simulation of the movements of children and adolescents.

Human morphology: its role in the mechanics of movement.

Growth across the lifespan of males and females produces change in the form and structure of the human body which must be recognized in biomechanical models. The different morphologies for age span, gender and racial groupings have been identified and quantified by anthropometrists working primarily with measuring sticks and tapes. These parameters are not the parameters used to solve the dynamics problems of human movement. Models of the body composed of joints and rigid links have been formed and the inertial properties of the segments are required. The research which has been conducted to estimate these segment inertias is incomplete, dispersed, often flawed and inconclusive. However, it is essential that we have a reasonable understanding of the differences in inertia between individuals and changes of inertia within the individual regardless of age, sex and race. Segment inertia parameters can provide valuable insight into growth and the differences between individuals and populations. Segment morphology ranges from embryonic to excessive and each stage of growth or development has potential for the investigation of relationships between shape, size, inertia, weight and movement. The purpose of this paper is to examine research into segment inertias which provides useful information about the differences and changes to be expected. Although some guidance is provided, particularly with respect to bench mark studies, the paper is not intended as a discussion of methodologies. The studies which are pertinent to changes and differences in inertia make it clear that there are many interesting differences between age spans and, within these, differences between males and females and between races. If, in place of the expediency of proportions, segment parameters were measured and integrated into all studies, we would have a more complete representation of morphological changes and differences.

Body segment mass, radius and radius of gyration proportions of children.

The segment inertial parameters of children are fundamental to the analysis and simulation of their movements. Generally it has been recognized that adult parameters cannot be extrapolated and most of the anthropometric data on children are of little or no use for determining inertias. Consequently, there have been few studies of children's kinetics. In response to this problem a longitudinal investigation, the Laurentian Study of Biomechanical Development, was launched and in this paper the effects of growth on selected segmental size and inertial parameters are reported for boys between the ages of 4 and 15 yr. The twelve subjects, representing heterogeneous body types were followed over 3 yr for a total of 36 observations. Elliptical zones 2 cm wide were used to model the body and segment inertias calculated using segment densities from the literature. These inertias were the mass, moment of inertia and mass centroid location for a fourteen segment planar representation of the body. The general accuracy mean error based on body mass was 0.203% which is consistent with reports from similar studies and techniques. Plots of segment mass proportions with respect to age showed a decrease in the head proportion balanced by increases in the thigh, shank, foot and upper arm proportions in particular. The trends for each segment were consistent with the trends for linear measures reported in the anthropometry literature. Radius proportions to the mass centroid and radius of gyration proportions were also plotted and showed smaller but consistent changes with respect to age. Linear regressions were then fitted to the distributions and standard errors calculated. The magnitude and slope of the regressions were for the most part consistent with a reported cross-sectional study of Japanese children. Where data were available, predicted parameters were compared with the reported parameters for a 12 yr old analyzed using a different mathematical model. Comparisons were also made between the predicted parameters at 15 yr and the reported parameters for healthy young adults who had been scanned using a gamma-radiation technique. For most parameters there was either good agreement or differences could be explained logically. The traditionally used parameters from older cadavers were quite inconsistent with the above. The variances of the 36 observations about the regression lines as indicated by the standard errors were small. As an illustration of the effect of these variances, the trunk parameters for a 10 yr old performing a standing jump for distance were decreased by 1 S.E. and this matched by increases for the thigh, shank and head.(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in segment inertia proportions between 4 and 20 years.

Growth between 4 and 20 yr produces an increase in body mass and a redistribution of that mass throughout the body. It is the purpose of this investigation to describe changes in the segment mass, radius to the mass centre and radius of gyration for a sample of males, 4-20 yr and the potential effects of these changes on joint reaction forces and moments. The data were collected annually over 9 yr in a mixed longitudinal study completed in 1985. Elliptical zones 2 cm wide were used to model the 16 segments of the body. From these and reported segment densities, mass, the coordinates of the mass centre and the principal moments of inertia were determined for the segments and the body. The parameters reported are the inertia parameters suitable for a sagittal planar analysis with the head and neck considered one segment and values given for other fused segments. The accuracy of the method was judged against the total body mass, and other accuracy estimates from the literature were examined. The parameters are presented as proportions of total mass or segment length. It is clear from the polynomial regressions that there is a substantial redistribution of the mass between segments and this is consistent with the principles of cephalo-caudal and distal-to-proximal development. The proportions for radius and radius of gyration indicate that mass redistribution within segments is comparatively small. The parameters for a 6 yr-old were compared to the parameters expected at 18, 24 and 54 yr and substantial differences noted.(ABSTRACT TRUNCATED AT 250 WORDS)

The application of segment axial density profiles to a human body inertia model.

The intention of this study was to construct segment density profiles and compare segment inertias calculated when uniform densities and profile densities are used in a mathematical model. Axial densities from computerized tomography (CT) slices for the body segments of a sample of Chinese females (Zheng et al., Proceedings of the Beijing Asian Games Scientific Congress, 1990) were used to form profiles which could be employed in body segment models. Polynomials based on proportion of segment length were fitted to the reported mean slice densities. These profiles were then used with five widely divergent samples (n = 10); young adult females, young adult males, infants, male children and elderly adults. The mathematical model used is based on an assumption that all segments can be represented by stacked elliptic cylinders. The results show that when the profile densities were substituted for average cadaver densities the increase in the estimated total body mass was less than 0.85%. For the individual segments, use of the profile rather than average density increased the average segment mass estimate by up to 2.7%. The centres of mass and the principal moments were affected by the variations in density along the axis as well as the magnitudes, by up to 0.54 and 3.8%, respectively. Although the effects of using the profiles appear to be small the differences for individual samples, segments and parameters ranged up to 22.5%. It is not possible to decide if average or profile densities produce more accurate estimates of inertia, but the profile allows for axial variation in density and is therefore recommended.

Distribution of mass to the segments of elderly males and females.

The comprehensive study of the motion of elderly men and women requires the knowledge about the distribution of the body mass to the segments. Cadaver studies are of older subjects and should provide this information. However, the small samples are primarily male and do not represent the body mass of the elderly. In this study a mathematical model which utilizes the shape of the front and side outlines to calculate segment volume, and subsequently mass, is used. Substantive modifications were made to expedite the original technique [Jensen, J. Biomechanics 11, 349-358 (1978)] by using images from two cameras and digitizing software to determine cross-sectional axes as segments are outlined. The revised technique was used in a study of 12 females and seven males, each 63-75 yr. The mean error for body mass estimation was 0.05% (S.D. 2.96%). The calculated masses were compared to estimated masses based on Dempster [Technical Report 55-159, Wright-Patterson Air Force base, Ohio (1955)], and for females, the Dempster proportions overestimated head and forearm mass and underestimated arm and thigh mass (p > 0.05). For males, the head mass was overestimated. The differences between male and female segment masses were then evaluated. Differences for all segments were significant, with the exception of the upper trunk and thigh. When body mass was considered, the female thigh and foot proportions were larger and the lower trunk, forearm and hand proportions smaller.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in segment mass and mass distribution during pregnancy.

The purpose of the study was to evaluate the rates of change in the estimated masses and principal moments of inertia of the body segments during the second and third trimesters of pregnancy. Fifteen subjects, on average 15.1 weeks pregnant, were tested monthly until term. The body was modelled as 16 segments consisting of 2 cm stacked elliptical cylinders sectioned in the transverse plane. Linear regressions were fitted to the segment inertias and regression coefficients determined for the individual growth curves. The mean rate of increase for the lower trunk mass was 0.29 kg per week and 0.0069 kg m2 per week for the transverse axis principal moment. Differences between the means of the segments for rates of change of mass and the three principal moments were then tested. All four ANOVAs used to test the differences were significant. The post hoc analysis established that over the second and third trimesters the lower trunk inertias increased at a greater rate than all other segments and there were no significant differences between the remaining segments. The effect of such changes in the trunk segment masses and principal moments was illustrated by an analysis of intersegmental dynamics during a sit to stand of one pregnant subject whose lower trunk mass increased from 21.6 kg to 28.4 kg. A knowledge of the differences in an individual's segment inertias should lead to a better understanding of how movements are affected during pregnancy.

A general Newtonian simulation of an n-segment open chain model.

This paper presents a set of general Newtonian equations which govern the simulation of movement of a body represented by n open chain links. The input for the simulation consisted of the joint moment of force histories, lengths, masses and moments of inertia, the initial absolute angular displacements and velocities and, for the fixed or constrained axis of the nth segment, the acceleration history. Angular accelerations were then determined by solving n linear equations simultaneously, and angular velocities and displacements determined by integrating forwards. The final output was in the form of a graphical display of the linked figure. Applications of the simulation were demonstrated using three-segment representations of movements of the upper and lower extremities and a five-segment representation of a jump. Good agreement was achieved between the displayed angular displacements for the original and simulated movements. The potential for varying the input data has been examined and the implications of anticipating the effects of changed torques, inertial characteristics including attached prosthetic or sports implements and/or the initial conditions for a movement are discussed.

Effects of dietary retinyl acetate on the promotion of hepatic enzyme-altered foci by polybrominated biphenyls in initiated rats.

Vitamin A inhibits the development of some chemically-induced tumours. Since polybrominated biphenyls (PBBs) are hepatic tumour promoters and they affect vitamin A homeostasis in rats, we put forward the hypothesis that dietary levels of vitamin A would influence tumour promotion by PBBs. In the study described here, female Sprague-Dawley rats were initiated on day 1 by ip administration of diethylnitrosamine. On day 7 after initiation, the rats were fed a vitamin A-deficient basal diet that was supplemented with either 2000 IU (low-vitamin A) or 200,000 IU (high-vitamin A) retinyl acetate/kg feed. From day 30 after initiation until the end of the study the following PBBs were added to the diets: Firemaster BP-6 (10 ppm), 2,4,5,2',4',5'-hexabromobiphenyl (10 ppm) or 3,4,5,3',4',5'-hexabromobiphenyl (1 ppm). The control animals received low- or high-vitamin A diets containing no PBBs. On day 180, the rats were necropsied, sections of various tissues were stained for histopathological examination and an evaluation of hepatic enzyme-altered foci was performed. Numbers of gamma-glutamyl transpeptidase-positive foci/cm3 liver and the mean volumes of these foci were lower in the high-vitamin A groups than those in the corresponding low-vitamin A groups, but these differences were not significant. The percentage of the liver volume occupied by foci was significantly greater in the low-vitamin A with 345-HBB group than in the corresponding high-vitamin A group. Thus, high dietary levels of vitamin A had some inhibitory effect on the promotion of hepatic-altered foci by 345-HBB in initiated rats.

Gravity constraints in infant motor development.

The effect of gravity in determining if and when during infancy movements eventuate and the rate at which they develop is unknown. In accordance with intersegmental relationships (Hof, 1992), a muscle moment during infancy would have to develop more rapidly than the gravitational moment before movement could occur. In this investigation, the effect of growth through the influence of gravity on the joint moments in the axial region when infants were in a prone or supine posture was examined. A mathematical model that considers the body to be composed of transverse elliptical cylinders, 1 cm deep and of known density, was used in estimating the mass of the 16 segments of the body. The gravitational moments about 3 joints within the axial region (C7-T1, T12-L1, and the hip) were determined by summation, using the radii from the joint transverse axis to the center of mass of the segments. Infants (N = 27) aged between 9 and 36 weeks at the beginning of the study were tested monthly 6 times, and the effect of growth on the gravitational moments was represented by first-order polynomials. Age x Joint analysis of variance (ANOVA) of the mean slopes of the regressions for the gravitational moments revealed significant main effects for age and joint. The means increased monotonically with the number of segments and decreased as infants aged. The mean slopes of the neck and trunk joints were significantly smaller than that of the hip joint. With increasing age, the gravitational slope was significantly smaller. The changes in the gravitational moments during infancy are seen as likely control parameters effecting phase shifts in motor patterns during development.

Effect of combined antibiotic therapy on fertility in brood bitches infected with Brucella canis.

Bitches with naturally occurring Brucella canis infection were treated with combined antibiotic therapy consisting of tetracycline, dihydrostreptomycin, and trimethoprim-sulfadiazine. After treatment, all but 1 bitch became abacteremic, and serologic titers declined for a variable length of time (3 months to 1 years). Abortion did not occur while these bitches were abacteremic. Although sequential antibiotic therapy for 6 weeks did not eradicate Brucella canis from affected bitches, it did not prevent abortion. The number of live pups whelped and weaned by treated bitches was comparable with that in bitches before they became infected.

Chronic active hepatitis in 26 Doberman pinschers.

Chronic active hepatitis with increased hepatic copper concentration was diagnosed in 25 female and 1 male Doberman Pinscher dogs. Common clinical signs included polyuria/polydipsia, weight loss, anorexia, icterus, and ascites. Increased liver enzyme activities and abnormal liver function test results were the most consistent clinicopathologic changes. The dogs were assigned to 3 groups on the basis of clinical course of the disease. Group 1 dogs (n = 12) had clinical signs of advanced liver failure and died within one week. Group 2 dogs (n = 7) had less severe clinical signs of liver disease and died within one month. Group 3 dogs (n = 5) did not have clinical signs of illness or had mild clinical signs of liver disease and died 1 to 42 months after initial evaluation. One dog could not be reevaluated and another dog was alive 3 months after initial examination. Treatments consisted of supportive care for dogs in group 1, and dietary manipulations and corticosteroids for dogs in groups 2 and 3. The association of increased liver copper concentration and chronic active hepatitis is not known.

[Oral ranula. A follow-up study]. / Mundbundsranula. En efterundersøgelse.

Ranula is a cystic swelling of the floor of the mouth, which is usually unilateral and relatively uncommon. The cyst arises from the sublingual salivary gland. We reviewed 14 patients operated in the period 1976-April 1998. There was no recurrence after marsupialization and after extirpation of the sublingual gland. Fourteen percent of the patients had recurrence after extirpation of the cyst. At the follow-up time (average 8.1 years) 18.2% had complications. We suggest that marsupialization/extirpation of the cyst should be primary treatment. In case of recurrence the sublingual gland should be extirpated.