Vertebral Sites Research Articles

A prospective and consecutive study of surgically treated lumbar spinal stenosis. Part I: Clinical features related to radiographic findings.

A prospective study of consecutive patients undergoing surgery for central lumbar spinal stenosis. To evaluate symptoms and signs in patients undergoing surgery for central spinal stenosis and to correlate the findings to age, preoperative duration of symptoms, and radiographically detected constriction. The degree of constriction of the spinal canal considered to be symptomatic of lumbar canal stenosis is not clear, nor is the relation between the clinical appearance of the disease and the degree of radiographically verified constriction. One hundred five consecutive patients scheduled for decompression surgery were included in a prospective study. The day before surgery, all patients were interviewed and examined, using a defined protocol that included data on age, gender, preoperative duration of symptoms, walking ability, and occurrence of pain at rest and at night. Included were data recording straight leg raising test results, reflex disturbance, and extensor hallucis longus muscle weakness. All radiographs were examined by a neuroradiologist. The anteroposterior diameters at each site from L1-L2 to L5-S1 were recorded. For the computer analysis, the site of and width at the narrowest site was registered, as well as the number of sites with an anteroposterior diameter of less than 10 mm. A statistical analysis was performed using chi-square analysis, nonparametric tests, analysis of variance, and logistic regression. Pain at rest and at night was reported by 68 and 60 patients, respectively, and was more common in younger patients (P = 0.065 and 0.015, respectively). A severe reduction of walking ability (< 0.5 km) was reported by 70 patients. The straight leg raising test results were negative in 70 patients, positive > 60 degrees in 16, positive 30-60 degrees in 14, and positive < 30 degrees in 5. Younger patients had a positive straight leg raising result (P = 0.028, analysis of variance) more often. Reflex disturbances correlated to patient age: Older patients had reflex disturbances more often. There was no correlation between preoperative duration and pain or neurologic disturbances: Patients with longer preoperative duration of symptoms did not demonstrate more severe symptoms. There was a total myelographic block of the spinal canal in 13 patients. The mean value of the antero-posterior diameter in the other patients was 6.8 mm (range, 4-11 mm). In patients younger than 70 years L4-L5 was the site for the most pronounced constriction, whereas L3-L4 was the narrowest site in the older patients. Degenerative spondylolisthesis was found in 32 patients, and they had a more pronounced constriction of the spinal canal (5.6 mm compared with 6.7 mm in those without displacement, P = 0.02). There was a (nonsignificant) tendency toward more walking disturbances in patients with a more pronounced constriction of the spine. There was no correlation between reflex disturbances or extensor hallucis longus weakness and radiographically detected constriction. Pain was more intense and positive straight leg raising test results were more common in younger patients, whereas reflex disturbances were more common in the elderly. The vertebral site for the lowest anteroposterior value was higher with higher age. Preoperative duration did not affect the severity of symptoms or signs. Patients with more pronounced stenosis tended to have a more severe reduction of walking ability. There was no correlation between symptoms and signs and radiographically detected constriction.

Structure of a fish ( Oncorhynchus mykiss) vitellogenin gene and its evolutionary implication

In this paper we describe the first complete structure of a fish vitellogenin gene. A 22 kb genomic region from rainbow trout ( Oncorhynchus mykiss) was cloned and analysed. This region was shown to contain two tandemly arranged vitellogenin genes. Both genes are 98.7% similar, indicating that they result from a recent local duplication. The complete sequence encoding one of the two genes was determined and the gene organization was established. The gene is 10.3 kb long and has 34 exons, it lacks one exon compared to amphibian and avian vitellogenin genes. Exons 22 and 23 of the Xenopus and chicken genes were shown to be merged into a single exon in the trout genome. Other splicing sites appeared highly conserved between the three vertebrate genes. In contrast, little similarity between invertebrate and vertebrate vitellogenin genes was observed with respect to the number and organization of introns. The comparison of 17 independent invertebrate splicing sites with the 34 vertebrate sites indicated that a few sites are probably ancient. However, most of the splicing junctions compared appeared unrelated. Results suggest that vitellogenin genes have been reshaped through multiple insertions and deletions of intervening sequences during evolution.

No loss of biomechanical effects after withdrawal of short-term PTH treatment in an aged, osteopenic, ovariectomized rat model

The aim of the study was to assess the biomechanical effects of short-term PTH treatment and withdrawal on bone mass and strength in an aged, osteopenic, ovariectomized (ovx) rat model. Additionally, the effect of sequential therapy with PTH and the bisphosphonate, risedronate, the effect of long-term PTH monotherapy, and the effect of long-term risedronate monotherapy were assessed. 96 4-month-old rats were randomized into nine groups. Eight groups were ovariectomized and one group was sham operated. 12 months after surgery, treatment regimens were initiated (0W) and were continued for either 2 weeks (2W) or 12 weeks (12W). The treatment regimens were as follows: (1) baseline ovx (0W); (2) ovx-saline (2W); (3) ovx-PTH 1–34 (2W); (4) intact-saline (12W); (5) ovx-saline (12W); (6) ovx-risedronate (12W); (7) ovx-PTH 1–34 (12W); (8) ovx-PTH 1–34 (2W), followed by pause (10W); and (9) ovx-PTH 1–34 (2W), accompanied by risedronate (12W). The effect of therapy (endpoint) was measured at three skeletal sites: vertebral bodies; femoral cortical bone; and femoral necks. The results revealed an anabolic, time-dependent effect of PTH 1–34 at all skeletal sites. No loss of anabolic effect was observed 10 weeks after discontinuation of 2 week PTH treatment in this rat model. Risedronate given in sequential therapy with PTH produced no significant effect on biomechanical properties at any skeletal sites when compared with 2 week PTH followed by a 10 week pause. However, when risedronate was given alone, a positive effect was seen at the vertebral site after a 12 week treatment. On the basis of this study with short-term PTH treatment of aged, osteopenic, ovariectomized rats, there seemed to be a significant effect of PTH on the biomechanical properties and no loss of effect even 10 weeks after PTH withdrawal.

Bone mineral density and L-thyroxine treatment in rapidly cycling bipolar disorder

The use of levothyroxine in higher doses, sufficient to suppress thyroid-stimulating hormone (TSH), has been shown in open and placebo-controlled crossover studies to be useful as an adjunctive treatment of the cycling behavior in patients with rapid-cycling bipolar disorder who are predominantly premenopausal women (Bauer and Whybrow 1990, 1991, Bauer et al 1994); however, we have been concerned about the risk of osteoporosis in this patient group, because exogenous thyroid hormone administration increases bone resorption and bone turnover (Baron and Braverman 1991). Indeed, some endocrinological studies indicate that externally administered thyroxine leads to decreased bone density in preand postmenopausal women (Baron and Braverman 1991 for review). Conversely, Franklyn et al (1992) recently found that premenopausal hypothyroid women treated with thyroxine did not develop a decrease in bone density in the vertebral and appendicular bone sites. There are no data on the effect of externally administered thyroxine on bone density on psychiatrically ill patients who receive this hormone to augment the effect of psychotropic medications. Hence, we now report a cross-sectional study undertaken to evaluate bone density in women with rapidly

Potentiels évoqués somesthésiques dans la polyarthrite rhumatoïde avec atteinte radiologique du rachis cervical

Somatosensory evoked potentials (SEP) have been recorded in 11 patients with cervical spine involvement, with or without signs of myelopathy due to rheumatoid arthritis (RA). In three patients, SEP have been recorded both before and after cervical spine surgery. In seven cases, the P14 (particularly the P9/P14 amplitude ratio) or P30 potentials were abnormal, whereas other potentials and conduction times were less often modified. Vertebral luxation sites that were predominantly observed at the upper cervical level account for these findings, thus supporting the diagnostic utility of P14 and P30 potentials which respectively take origin in the lower brain stem, close to or into the nuclei cuneatus and gracilis. Postoperative SEP were strongly correlated with the surgical outcome. SEP could be abnormal in the absence of overt clinical myelopathy or vertebral luxations, thus revealing infraclinical damage to the somatosensory pathways. This suggests that SEP recording is useful to discriminate RA patients with upper cervical cord dysfunction from those in whom vertebral lesion proves to have no direct impact on somatosensory conduction.

Genetic variability in adult bone density among inbred strains of mice

More than 70% of the variability in human bone density has been attributed to genetic factors as a result of studies with twins, osteoporotic families, and individuals with rare heritable bone disorders. We have applied the Stratec XCT 960M pQCT, specifically modified for small skeletal specimens, to analyses of bones from 11 inbred strains (AKR/J, BALB/cByJ, C3H/HeJ, C57BL/6J, C57L/J, DBA/2J, NZB/B1NJ, SM/J, SJL/BmJ, SWR/BmJ, and 129/J) of female mice to determine the extent of heritable differences in peak bone density, pQCT scans were taken of femurs from (a) 12-month-old inbred strain females and (b) a subset of four strains (C3H/HeJ, DBA/2J, BALB/cByJ, C57BL/6J) at 2, 4, and 8 months. In addition, pQCT scans were also obtained from L5-L6 vertebrae and proximal phalanges from the same subset of four inbred strains at 12 months of age. Comparison of bone parameters among inbred strains revealed significant differences at each of the three sites investigated. Femoral and phalangeal bones differed among strains with respect to total and cortical density, mineral, and volume. Only cortical bone parameters were significantly different among strains at the vertebral site. With respect to strain differences, the highest value for any given bone parameter was found in the C3H/HeJ strain, whereas C57BL/6J values were absolutely, or statistically, the lowest. Similarly, with respect to bone sites, cortical bone density was significantly correlated among strains. On the other hand, we found that none of the femur, vertebral, or phalangeal parameters correlated with body weight, even though body weight varied by 86% among those inbred strains. The developmental studies of femurs conducted at 2, 4, and 8 months of age with C3H/HeJ, DBA/2J, BALB/cByJ, and C57BL/6J females showed differences in total density among strains at 2 months and thereafter. Adult peak bone density was typically achieved by 4 months, whereas femurs continued to lengthen for 4 to 8 months thereafter. We conclude that (1) major genetic effects on femoral, vertebral, and phalangeal bone density are detectable among inbred strains of mice; (2) cortical bone density shares common genetic regulation at the three measured sites; and (3) within the femur, genes that regulate length and density are different.

L-thyroxine not influence bone mass: A study wity dual energy X ray densitometry (dexa) at lumbar and vertebral sites

L-thyroxine not influence bone mass: A study wity dual energy X ray densitometry (dexa) at lumbar and vertebral sites

Physiological correlates of vagal nerve innervation in lower vertebrates

In lower vertebrates, cardiac vagal innervation shows less anatomic complexity and specialization than in mammals. To assess the physiological development of vagal specialization in the vertebrates, we investigated cardiac chronotropic effects of electrical stimulation of left and right vagus nerves separately and the interactions between both nerves in anesthetized animals from three vertebrate groups, toad (Bufo marinus), shark (Heterodontus portusjacksoni), and lizard (Physignathus lesueurii). Atropine-sensitive slowing was effected equally by left or right vagi in all species, and chronotropic effects of simultaneous stimulation were the same as the sum of left and right responses. In sharks and lizards, no slowing after atropine was detected (10 Hz stimulation). In toads, after atropine, cardiac slowing was elicited equally by left or right vagal stimulation > 2 Hz. Simultaneous stimulation of both vagi after atropine caused significantly greater slowing than the sum of left and right responses. The results suggest even distribution of left and right vagal nerve endings to pacemaker cells, and limited competition for cardiac receptor sites in lower vertebrates.

Influence of spontaneous calcium intake and physical exercise on the vertebral and femoral bone mineral density of children and adolescents

Peak bone mass is determined mainly by genetic-ethnic factors, but environmental factors such as calcium intake and physical activity during childhood and adolescence could play a role. We have measured the bone mineral density (BMD) of 151 healthy children and adolescents, ages 7-15.3 years. Density was measured by dual X-ray absorptiometry (DXA) at two sites (lumbar verterbrae L1-L4 and the upper femur), and the data were analyzed in terms of the height, weight, sexual maturation, spontaneous calcium intake, and physical activity. Of the children, 57-71% had calcium intakes below 1000 mg/day. BMD increased with pubertal maturation from 0.68 +/- 0.08 to 0.92 +/- 0.09 g/cm2 (vertebral bone density, VBD) and from 0.87 +/- 0.10 to 1.03 +/- 0.09 g/cm2 (femoral bone density, FBD) between Tanner stage 1 and 5. Multiple regression analysis showed that body weight and Tanner stage were main determinants of bone density when expressed as g/cm2. The weekly duration of sports activity also influenced both the vertebral (p < 0.001) and femoral (p = 0.01) sites, especially in girls and during puberty. Dietary calcium appeared to be another independent determinant of BMD, especially before puberty, at the vertebral (p = 0.02) site. Most important, dietary calcium was found to be the main determinant of vertebral mineral density, when expressed as z score, in both sexes. Moreover, 93% of the 28 children with low vertebral z score values (below -1) and 84% of the 31 children with low femoral z score values (below -1) had dietary calcium intakes below 1000 mg/day.

Dual-energy X-ray absorptiometry of the calcaneus: Comparison with vertebral dual-energy X-ray absorptiometry and quantitative computed tomography

The purpose of this study was to determine the efficacy of using bone mineral measurements of the calcaneus to evaluate osteoporosis. Dual energy X-ray absorptiometry (DXA) of the calcaneus was compared with posteroanterior lumbar absorptiometry (DXA) and vertebral quantitative computed tomography (QCT) measurements in 171 white women (78 normal and 93 osteoporotic). DXA measurement of os calcis mineralization decreased significantly in osteoporosis, but to a lesser extent than in vertebral sites. In normal subjects, good correlations were observed between calcaneal and lumbar DXA (0.69) and QCT (0.56). In subjects with vertebral fractures, there was also good correlation between calcaneal DXA and QCT (0.59-0.69). This suggests that trabecular bone in calcaneus and vertebrae have related involution in cases of vertebral osteoporosis. However, the extent of bone loss is less marked in the calcaneus than in the vertebrae and is not sufficient to be accurately measured over time. We conclude, therefore, that although the global densitometric measurement at this site is not sufficiently sensitive for general use, it can be useful as a epidemiological research tool.

Trabecular and cortical bone changes in vertebral and peripheral skeletons induced by surgical menopause

Using dual x-ray absorptiometry (DXA), quantitative computed tomography (QCT), and microdensitometry (MD) methods, we performed a 3-year longitudinal study of bone changes induced by surgical menopause, i.e., hysterectomy with unilateral or bilateral oophorectomy (OVX), in 52 nonmenopausal women. In the trabecular spine, bone mineral content (Dc) and bone mineral density (Dd) were determined by DXA, and bone mineral density (L2 and L3) was determined by QCT. In the cortical metacarpals, cortical thickness (MCI) and bone mineral density (GSmin/max and ∑ GS/D) were determined by MD. Bone reduction in axial and peripheral body sites was evaluated by all determinations 2.92 years after OVX. In the bilateral OVX group, accelerated bone changes began to appear immediately after OVX, and this rapid phase of bone loss persisted in the follow-up period. In the unilateral OVX group, however, no accelerated changes were detected and the slow phase of bone loss continued throughout the follow-up period; bone reduction in the bilateral group was thus greater than that in the unilateral group. Although there was a significant correlation between trabecular and cortical bone changes, the discrepancies between DXA, QCT, and MD determinations at the two body sites meant that it was not possible to precisely predict one bone measurement from another. The reliability of DXA and QCT determinations was not significantly different, and these two determinations afforded better discrimination than MD for detecting accelerated trabecular bone changes in the rapid phase early after OVX. The sensitivity of indices in MD for detecting cortical bone mass change was found to be, in descending order, MCI, GSmin/max, and ∑ GS/D, whereas on the MD determination, the sensitivity for the follow-up of bone changes was in the reverse order. MD was more suitable for discriminating the small cortical bone changes in the prolonged slow phase after OVX. To evaluate the influence of surgical menopause by determining differential trabecular and cortical bone changes, simultaneous assessment at both vertebral and peripheral sites was indispensable. Changes in the peripheral metacarpals did not prove to be a reliable indicator of changes in the axial spine.

Assessment of vertebral canal diameter and bony malformations of the cervical part of the spine in horses with cervical stenotic myelopathy

Summary Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (msd) values and application of the established msd values for diagnosis of cervical stenotic myelopathy (csm). Variability in msd determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The msd of the vertebral canal was determined in 50 horses with csm and 50 control horses, using a radiopaque marker method for correction of magnification. In addition, a ratio of the absolute msd to the sagittal width of the vertebral body and a ratio of the absolute msd to the length of the vertebral body were determined in 100 csm-affected and 100 control horses. Response operating characteristic curve analysis of each method determined that the sagittal ratio method of canal diameter assessment provided the most accurate interpretation of cervical radiographs for diagnosis of csm, with sensitivity and specificity of ≥ 89% at each vertebral site. The accuracy of the ratio method, without consideration of bony malformation, supports the importance, and perhaps prerequisite, of generalized vertebral canal stenosis in the pathogenesis of csm. Subjective evaluation of bony malformations from cervical radiographs of 100 csm-affected horses and 100 control horses indicated that csm-affected horses have more severe bony malformation than do control horses. However, moderate to marked degenerative joint disease of the articular processes was frequently observed in control horses. Subjective evaluation of bony malformation does not distinguish between csm-affected and unaffected horses.

Morphometrical Analysis of the Cervical Vertebrae of Thoroughbred Foals.

Morphometrical analysis of the cervical vertebrae of thoroughbred foals was performed by a principal component analysis method. Foals without any spinal ataxia, consisting o f 26 males (4-21 months of age) and 13 females (5-23 months of age), were used. The cervical vertebrae ( from C3 to C7) were collected from these foals and bone morphometry on 28 measurements in each vertebra was performed. As a result, the first, second and third principal components were considered as the size, shape and sex factor, respectively. The combination o f the first and second principal components discriminated each cervical vertebral site clearly. The characteristic relationship between the second principal component and age was defined.

Morphological analysis of cervical vertebrae in ataxic foals.

Morphological differences between cervical vertebrae were statistically analyzed in ataxic foals to clarify abnormal structural factors in the pathogenesis of this problem. At first, multiple regression analysis and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differences in the growth of all cervical vertebral sites, and the most suitable categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sites in the cervical vertebrae. Twenty-eight ataxic and 19 control foals at the age of 13 months or older were then used for discriminant analysis with 20 variables. As a result, 1-7 variables on C3-C7 were selected for sufficient discrimination, in which the heights of the cranial and caudal orifices of the spinal canal, longitudinal length of the vertebral head and height of the vertebral fossa strongly contributed to the discrimination of all the cervical vertebrae. In addition, the widths and longitudinal diameters of the articular processes on articular surfaces strongly contributed to the discrimination of the caudal region of the neck. In conclusion, it was suggested that the lesion in the cervical spinal cord observed in ataxic foals was caused by morphological abnormalities including osteochondrosis and subsequent degenerative joint disease in the cervical vertebrae.

Importance of bone resorption in the determination of bone density in women more than 10 years past the menopause

There is general agreement that bone density falls with age and is higher in heavy people than light people. We have studied a variety of potential correlates of vertebral, ankle, and hip bone density to evaluate other potential influences on the skeleton. We recruited 196 healthy women who were more than 10 years past the menopause and collected a diet and activity record, a 24 h urine, and a fasting blood and urine specimen. These blood and urine samples were analyzed for factors related to calcium homeostasis. We then measured bone density at lumbar vertebrae 1-4 and the hip and the ankle bone density of the nondominant leg. Correlations between vertebral, hip, and ankle bone density and other measured variables were explored using the statistical package SPSS PC. At the vertebral site, in addition to correlations with age and body mass index (BMI), a negative correlation with a measure of bone resorption, the hydroxyproline creatinine ratio (OHPCR), was noted. At the ankle site, in addition to correlation with age, BMI, and OHPCR, a positive correlation with activity and a negative correlation with serum calcitriol were noted. At the hip site, as well as age, BMI, and OHPCR, significant correlations with GFR and dietary calcium intake were noted. These data suggest that even in women 10 years past the menopause bone resorption has a significant effect on bone density, that renal function may account for some of the variance in bone density at the hip, and that activity effects are more marked at sites of greater loading, namely the ankle.

The assessment of vertebral deformity: a method for use in population studies and clinical trials.

The absence of specific criteria for the definition of vertebral fracture has major implications for assessing the apparent prevalence and incidence of vertebral deformity. Also, little is known of the effect of using different criteria for new vertebral fractures in clinical studies. We therefore developed radiological criteria for vertebral fracture in women for assessing both the prevalence and the incidence of vertebral osteoporosis in population and in prospective studies and compared these with several other published methods. Normal ranges for vertebral shape were obtained from radiographs in 100 women aged 45-50 years. These included ranges for the ratios of anterior/posterior, central/posterior and posterior/predicted posterior vertebral heights from T4 to L5. The predicted posterior height was calculated from adjacent vertebrae. In contrast to other methods, our definition of fracture required the fulfillment of two criteria at each vertebral site, and was associated with a lower apparent prevalence of fracture in the control women due to a lower false positive rate. The prevalence and incidence of vertebral deformity using different criteria were then compared in a series of women with skeletal metastases from breast cancer in whom radiographs were obtained 6 months apart. The prevalence of vertebral deformity and the specificity for deformity varied markedly with differing criteria. Using a cut-off of 3 standard deviations the prevalence of vertebral deformity in the women with breast cancer was 46%. Using other methods, the prevalences of deformity ranged from 33% to 74%. Over a 6-month interval 25% of patients with breast cancer sustained 61 deformities using our method, of which only 8% resulted from errors in reproducibility. The number of patients sustaining new deformities was increased twofold when assessed by other methods (45%-53%), but errors of reproducibility may have accounted for 21% of the new deformities. The magnitude and distribution of these errors have important implications for the apparent therapeutic efficacy of agents in clinical trials of osteoporosis. The rapid semi-automated technique for assessing vertebral deformities on lateral spine radiographs that we have developed has a high specificity, and reduces the impact of errors of reproducibility on estimates of prevalence and incidence. The method should prove a value in assessing vertebral deformity both in population studies and in prospective clinical trials.

The natural history and management of symptomatic and asymptomatic vertebral hemangiomas.

Fifty-nine cases of vertebral hemangioma were seen at the Mayo Clinic between 1980 and 1990. Vertebral hemangiomas were discovered incidentally in 35 patients, while pain was the presenting complaint in 13 patients. Five patients presented directly with progressive neurological deficit requiring surgery, and six patients had surgery elsewhere for spinal cord compression and were referred for follow-up evaluation. To better define the natural history of these lesions, a historical review of these patients was conducted; progression of an asymptomatic or painful lesion to neurological symptoms was found in only two cases (mean follow-up period 7.4 years, range 1 to 35 years). New-onset back pain followed by subacute progression (mean time to progression 4.4 months, range 0.25 to 12 months) of a thoracic myelopathy was the most common presentation for patients with neurological deficit. Initially, all 11 patients with spinal cord compression underwent decompressive surgery with full neurological recovery. Recurrent neurological symptoms were observed in three of six patients following subtotal tumor resection and postoperative administration of 1000 cGy or less radiation therapy (mean follow-up period 8.7 years, range 1 to 17 years). No recurrences were noted in four patients who had subtotal excision plus radiotherapy between 2600 and 4500 cGy. One other patient had gross total tumor removal without radiotherapy and has not had a recurrence. Based on these patients and a review of the literature, the authors recommend annual neurological and radiological examinations for patients with hemangiomas associated with pain, especially young females with thoracic lesions in whom spinal cord compression is most likely to develop. Radiation therapy or embolization is an effective therapeutic alternative for patients with severe medically refractory pain. Regular follow-up monitoring for patients with asymptomatic lesions is unnecessary unless pain develops at the appropriate spinal level. It is concluded that management of patients with a progressive neurological deficit should include preoperative angiography and embolization, decompressive surgery with the approach determined by the degree of vertebral involvement and site of spinal cord compression, and postoperative radiation therapy in patients following subtotal tumor removal. Operative management and complications are discussed.

Vertebral deformity in men.

Vertebral fracture is the most prevalent manifestation of osteoporosis in women, but there is very little information concerning vertebral fracture in men. These studies begin to determine the prevalence, radiographic character, and relationship to bone mineral density of vertebral deformity in men. A group of 144 white men aged 34-94 years (83% between 50 and 80 years) were studied. Thoracic and lumbar spine radiographs were obtained using standardized techniques, and morphometric measures of vertebrae (T6-L5) were obtained using a computerized digitization pad. Vertebral deformities (wedge, midbody, and crush) were identified using several criteria. In addition, a skeletal radiologist independently identified vertebral deformities, as well as vertebrae affected by epiphysitis (Scheuermann's disease), using classic radiographic criteria. Bone mineral density was measured at lumbar spine and proximal femoral sites using dual-photon absorptiometry. The prevalence of vertebral deformity was related to the criteria used for their identification. Utilizing vertebral-specific criteria (anterior/posterior or midbody/posterior vertebral height more than 3 SD below vertebral specific mean), 10% of subjects had vertebral deformity. Wedge deformity occurred primarily in thoracic vertebrae and were more common than midbody deformity, which occurred more commonly in lumbar vertebrae. Crush deformities were not observed. Evidence of vertebral epiphysitis was present in 9% of subjects but was not responsible for vertebral deformity sufficient to be falsely identified using the more than -3 SD criterion. Bone mineral density in subjects with vertebral deformity was clearly reduced at both vertebral (p = 0.003) and proximal femoral (p = 0.002) measurements sites. The number of vertebral deformities was negatively correlated with vertebral bone mineral density.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term thyroxine treatment and bone mineral density

Studies of the effect of thyroxine replacement therapy on bone mineral density have given conflicting results; the reductions in bone mass reported by some have prompted recommendations that prescribed doses of thyroxine should be reduced. We have examined the effect of long-term thyroxine treatment in a large homogeneous group of patients; all had undergone thyroidectomy for differentiated thyroid cancer but had no history of other thyroid disorders. The 49 patients were matched with controls for age, sex, menopausal status, body mass index, smoking history, and calcium intake score; in all subjects bone mineral density at several femoral and vertebral sites was measured by dual-energy X-ray absorptiometry. Despite long-term thyroxine therapy (mean duration 7·9 [range 1-19] years) at doses (mean 191 [SD 50] μg/day) that resulted in higher serum thyroxine and lower serum thyrotropin concentrations than in the controls, the patients showed no evidence of lower bone mineral density than the controls at any site. Nor was bone mineral density correlated with dose, duration of therapy, or cumulative intake, or with tests of thyroid function. There was a decrease in bone density with age in both groups. We suggest that thyroxine alone does not have a significant effect on bone mineral density and hence on risk of osteoporotic fractures.

On the action of RH 5849, a nonsteroidal ecdysteroid agonist, on a cell line from Chironomus tentans

AbstractRH 5849 competes with 3H‐ponasterone A for ecdysteroid binding sites in Chironomus tentans cells with an about fourfold lower relative affinity as compared to 20‐OH‐ecydsone. It does not interfere with glucocorticoid and estrogen binding sites in vertebrates. It is also not recognized by an ecdysteroid antibody. RH 5849 exerts typical morphological and physiological effects ascribed to the action of 20‐OH‐ecdysone on C. tentans cells, namely an increase in acetylcholinesterase activity and an inhibition of chitin synthesis.