摘要:

AbstractA group of 223 military recruits aged 18–21 years underwent strenuous physical training for a period of 14 weeks. The absolute bone density of the distal tibia in both lower limbs was measured before the training period and at its end. The density was determined by the Compton scattering technique, which has been developed in our laboratory; this method provides the bone mass of all bone constituents per unit volume. The distribution curve of the bone density in both tibiae shifted to higher values at the end of the training period. The mean bone density in the right and left tibia increased significantly by 7.5%. This study indicates that following an intensive physical exercise regime, a significant increase in the mass density of bone can be obtained in young adults within a short perio

ISSN:0736-0266    

DOI:10.1002/jor.1100070112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractWe report on data relating to nonalcoholic carbonated beverage consumption and bone fractures in 5,398 college alumnae, 2,622 former college athletes and 2,776 nonathletes, who responded to a detailed mailed questionnaire. A statistically significant association between nonalcoholic carbonated beverage consumption and bone fractures was found only in the former athletes, not the nonathletes. Among the athletes, the age‐adjusted odds ratio (OR) for the association of drinkers (yes/no) with any fracture (yes/no) was 1.35,95% confidence limits (CL) (1.14, 1.59). The dose‐response relationship between the amount of carbonated beverages consumed daily and the number of bone fractures of the athletes was also statistically significant. Results of multiple logistic regression analysis, which included only alumnae ≥50 years of age and which controlled for current exercise and other potential confounding factors, were as follows:(a) for athletes, the OR for the association of drinking nonalcoholic carbonated beverages and a first bone fracture at or after age 40 was 2.28, 95% CL (1.36, 3.84); (b) for all alumnae, a low milk diet was a risk factor for first bone fractures at or after age 40, OR = 1.92, 95% CL (1.15, 3.16); (c) former college athletes had a significantly lower risk offirstfractures at or after age 40 than did nonathletes; OR = 0.63, 95% CL (0.40, 0.99). The deleterious effect of nonalcoholic carbonated beverage consumption on the risk of bone fractures has not been reported, as far as we know. These results, if confirmed, may have important public health implications because of the 300% increase in carbonated beverage consumption combined with a decline in milk consumption in the U.S. over the last three de

ISSN:0736-0266    

DOI:10.1002/jor.1100070113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effects of systemically administered calcitonin (CT) on fracture healing were analyzed in an experimental study on rats. The healing of a fracture was followed from 3 days up to 9 weeks postoperatively. Half of the rats in each age group were given daily CT 10 MRC‐U/kg body wt s.c. Mechanical properties of the healing tibial fractures (tension strength) as well as various connective tissue components of the callus tissue were analzyed. No difference in the radiological or microscopical appearance of the fractures was detectable between the animals receiving CT and the controls. In the biochemical analysis matrix production as assessed from the concentrations of nitrogen, hexosamines, and hydroxyproline within the callus followed the usual lines of undistributed fracture union without any difference between the groups with and without CT. No differences could be detected in the mineralization of the callus between the specimens from animals receiving CT and those without. The tensile strength values of the fractures increased almost linearly up to 9 weeks. At 1 week the tensile strength values for fractures union in the animals without CT were ∼50% higher, but later on no differences could be detected between the groups. These results indicate that although in the early phases of long‐term CT therapy collagen synthesis may be impaired, there will be no effect on the net content of collagen or calcifying tissue in the callus or on the mechanical strength of healing frac

ISSN:0736-0266    

DOI:10.1002/jor.1100070114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractSpinal fixation employing transpedicular screws has recently been the focus of increased attention at various institutions throughout the world, but concerns about the safety and efficacy of transpedicular screws linger. This study was undertaken to address some of these concerns. The study included evaluation of the internal and external morphology of the vertebral pedicles, which revealed that adequate bone stock is generally available at T2, T7, T12, and L1–L5 spinal levels to accept screws in the 4–7‐mm diameter range. The pedicle was observed to be composed of abundant cancellous bone internally with relatively thick cortical walls. The method of pilot hole preparation for pedicle screws was also examined. Screws inserted in pilot holes prepared with a 3.4‐mm blunt probe (ganglion knife) resulted in higher pullout forces in eight of 10 trials as compared with those with pilot holes prepared using a 3.2‐mm drill. Furthermore, the probes afford greater control of hole depth and alignment. Fatigue studies on three screws designs revealed a graduation of strength between a 7.0‐mm pedicle screw, and a modified 6.5‐mm cancellous lag screw. The modified cancellous lag screw has an inherent stress riser that affected fatigue life. It was noted that extreme care must be exercised to prevent bending of the pedicle screws during implantation. If bending ocurs one can expect a 50% reduction in the number of cycl

ISSN:0736-0266    

DOI:10.1002/jor.1100070115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe variation in the dimensions of the lumbar spinal canal under both flexion‐extension and axial compression‐distraction was studied using computerized tomography (CT) scans in human cadaver lumbar spine specimens. In 3‐mm‐thick CT slices through the disk at L3‐L4, the cross‐sectional area of the spinal canal was reduced by around 40 mm2, corresponding to a 16% reduction of the initial area when the lumbar spines were moved both from flexion to extension and from distraction to compression. A corresponding reduction in the midsagittal diameter of the canal of 2 mm was found. During these motions, the ligamentum flavum did not appear to be a significant factor for the dynamic changes affecting the dimensions of the canal. This held true even after the disk had been excised in order to produce a total collapse of the

ISSN:0736-0266    

DOI:10.1002/jor.1100070116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThree rows of six evenly spaced 0.5 mm metal beads were implanted midsagittally into the discs of ten L4–5 human lumbar motion segments. The intradiscal bead displacements in response to compression, flexion, and extension loads were obtained by digitizing the bead positions from sagittal plane radiographs taken before and during the load application. Each disc was denucleated and the loading process was repeated. For the intact discs, in compression, the intradiscal bead displacements were predominantly anterior. In flexion, the beads in the center of the disc moved posteriorly whereas the beads closer to the periphery of the disc moved anteriorly. In extension, the central beads moved anteriorly and the beads closer to the periphery of the disc moved posteriorly. After denucleation, the bead displacements for compression and flexion implied an inward bulging of the inner wall of the annulus, despite outward bulging of the disc surface. We hypothesize that the inward bulging causes radial tensile stresses within the disc, leading to disruption of adjacent layers of annulu

ISSN:0736-0266    

DOI:10.1002/jor.1100070117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractArticular geometry of the tibia has been studied in relation to the functional axis and extra‐articular bone landmarks, using a Cartesian coordinate system. Thirty‐one cadaver limbs were used, 26 of them paired. The donor age range was 61 to 89 years (17 females, 14 males), none of whom showed evidence of significant arthritic deterioration. Most linear parameters were greater in males than females (p<0.005), and correlations between these parameters were noted, e.g., tibial length versus plateau width (r = 0.7, p<0.01) with both genders combined. Gender differences occurred in only two of the angular parameters—tibial torsion (p<0.025) and foot rotation (p<0.005). For the latter, mean rotation was internal (−5°) for males, and external (11°) for females. No correlations between angular parameters were found. In the paired limbs, there was asymmetrical distribution of just two parameters—varus tilt of the tibial plateau margins (p<0.005) and lateral deviation of the tuberosity (p<0.025). The data complement a previous report on the femur. These studies are relevant to the kinematics of the lower limb, design and sizing of resurfacing components, and possibly to the pathogenesis of ost

ISSN:0736-0266    

DOI:10.1002/jor.1100070118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractMany factors determine the scientific merit of an NIH research grant application. This paper is intended to help optimize the organization and logical development of investigators' research ideas so that grant applications will be evaluated by the reviewers in as favorable a light as possible. The ingredients of a successful grant application are good ideas, good science, and a good application. The research should be based on a significant hypothesis and, if possible, oriented towards uncovering an important biological mechanism. Specific methods should be directly related to each aim of the project. Likewise, the specific aims should be related to each hypothesis. All aspects of the application should be clear and focused. It is best to define all assumptions, limitations, and alternative approaches. In general, the best philosophy is for the applicant to address all possible problems before the reviewers do.

ISSN:0736-0266    

DOI:10.1002/jor.1100070119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractSerum muscle enzyme activities of eight healthy men (22–32 years old) were measured before and 48 h after separate bouts of repetitive concentric, eccentric, and isometric contractions of the lower leg anterior compartments. Serum creatine kinase and glutamic oxaloacetic acid transaminase levels were both elevated 2 days after the eccentric exercise regimen, exclusively (36 and 17%, respectively). Lactic dehydrogenase levels were not affected by any of the protocols. Delayed muscle soreness was exclusively reported from the eccentrically exercised limb. We suggest that the high tensions developed during eccentric exercise cause mechanical damage, possibly including sarcolemmal degeneration. Subsequently, muscle enzymes are released to the blood. We conclude that postexercise serum levels of some muscle enzymes, at the time of maximal soreness, are qualitative markers of muscle damag

ISSN:0736-0266    

DOI:10.1002/jor.1100070120

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractArticular cartilage and the intervertebral disc tissues have different material and biological properties and different patterns of aging and degeneration. To determine if the proteoglycans of these tissues differ in structure, we used the electron microscopic monolayer technique to compare baboon articular cartilage proteoglycans with baboon annulus fibrosus, transition zone, and nucleus pulposus proteoglycans. Intervertebral disc and articular cartilage porteoglycans differed signficantly. Articular cartilage contained large proteoglycan aggregates formed from hyaluronic acid central filaments, multiple monomers, and large nonaggregated monomers. These molecules were identical to those of nasal cartilage, growth plate cartilage, chondrosarcomas, or menisci. In contrast, the intervertebral disc tissues contained only nonaggregated proteoglycan monomers and clusters of monomers without apparent central filaments. Intervertebral disc nonaggregated monomers were shorter and more variable in length than those from articular cartilage, and nucleus pulposus nonaggregated monomers were even shorter and more variable in length than transition zone and annulus fibrosus monomers. These observations suggest that significant differences in proteoglycan metabolism exist between articular cartilage and intervertebral disc.

ISSN:0736-0266    

DOI:10.1002/jor.1100070121

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY