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Biomedical subjects

C Wüster

Publications and source records attributed to C Wüster.

At least 19 recordsLinked to original sources

[Multiple endocrine neoplasia associated with multiple lipomas].

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN-1) is characterized by tumors of the parathyroids, the neuroendocrine pancreas-duodenum and the anterior pituitary, but shows also a wide clinical variety of other symptoms. CASE REPORT: We present a case of a 68-year-old woman with a 18 year history of MEN-1 consisting of gastrinoma and primary hyperparathyroidism. Beside these typical symptoms, the patient suffered from thyroid adenoma, malignant kidney tumor and multiple subcutaneous lipomas. RESULT: While the number of autopsies declined from 113 in 1977 to 66 in 1984, the number of diagnostic techniques used increased continuously (94, 107, 118 and 140, amounting to 0.83, 1.34, 1.76 and 2.12 per patient). The premortal detection of abdominal abnormalities increased globally from 16.8 to 32.5%. This increase was largely due to better diagnosis of liver and gallbladder abnormalities which were in most cases of little relevance. CONCLUSION: Whether these non-endocrine tumors are associated to MEN-1 is unclear and has to be tested by examining the chromosomal regions 11q13 and 11q24/25 of the tumors sample, in which the possible MEN-1 involved tumor suppressor genes are located.

Aged

[Vertebral deformity as an index of osteoporosis-induced spinal fracture--an external validity construct based on bone density data].

BACKGROUND: In order to test the validity of vertebral morphometry for the assessment of prevalent vertebral osteoporotic fractures, we examined the association between vertebral deformities and bone mineral density (BMD). METHOD: The study population consisted of 595 postmenopausal women and 581 men aged 50 to 82 years who participated in the baseline survey of the European Vertebral Osteoporosis Study (EVOS) in Germany and received BMD measurements by dual-X-ray-absorptiometry (DXA) at the femur and the lumbar spine. RESULTS: In both sexes only vertebral deformities defined by more stringent morphometric criteria (McCloskey; Eastell 4 SD criterion) were significantly and inversely related to BMD (odds ratios 1.42 to 3.21 for a 1 SD [standard deviation] reduction in BMD; p < 0.05). The strength of the association depended on the stringency of the morphometric algorithm applied, and on the site of BMD measurement. The strongest associations were observed with femoral neck BMD in women and with BMD at the lumbar spine in men. In contingency analyses between vertebral deformities and osteoporosis (WHO criteria; European young female BMD reference values), vertebral deformities proved to be highly specific by all methods, even slightly more so in men (87.8 to 97.5%) than in women (86.3 to 96.7%). The predictive value of a positive test with respect to vertebral osteoporosis reached a maximum value of about 50% in both sexes. It further increased up to 72%, when the definition of osteoporosis was based on low BMD values at either the spine or the femoral neck, but only in women. CONCLUSIONS: In conclusion, for both men and women the likelihood of vertebral deformities to be related to osteoporosis increases with the stringency of the morphometric method, with a similar probability of major deformities to represent vertebral osteoporotic fractures in men as in women. Nevertheless, even the most stringent morphometric criteria are not sufficiently valid instruments for the assessment of the prevalence of vertebral osteoporotic fractures in epidemiological studies.

Aged

[Osteosonography of the phalanges of men].

BACKGROUND: The distal metaphysis of the first phalanx of the fingers II to V is, like the vertebral body, a useful site for the measurement of mineralisation and structure of the bone, because of the simultaneous presence of compact and trabecular bone. METHOD: With an osteosonographic device (DBM sonic 1200, IGEA, Italy) we measured in 38 young and healthy men, 14 elderly and healthy men, 18 men with osteopenia, 8 men with osteoporosis and vertebral fractures and 10 men with long-standing cortisone medication, the adSOS (amplitude-dependent speed of sound) and the UBPS (ultrasound bone profile score) at the phalanges, as well as bone mineral density (BMD) at lumbar spine using dual-X-ray absorptiometry (DXA). RESULTS: There was no correlation between adSOS or UBPS and lumbar BMD (DXA). There was a significant positive correlation between adSOS and UBPS, r = 0.826 (p < 0.00001). AdSOS declined with age (r = 0.694, p = 0.021); the UBPS was not age-dependent (r = -0.15, p = n.s.), as expected. AdSOS and UBPS could discriminate significantly between the young and healthy controls and the men with osteopenia/vertebral fractures or oral steroids (p < 0.00001). The DXA could be significantly discriminate all healthy controls from the patients with osteopenia or vertebral fractures. It could not significantly discriminate the healthy controls from the patients taking oral glucoconticoids. Only the UBPS could significantly discriminate this group from the healthy controls. CONCLUSION: These results show, that adSOS and UBPS are precise parameters to be measured at the phalanges. The detection level of pathological changes in osteoporosis are similar between adSOS and lumbar BMD (DXA) and improved by using UBPS. This might be explained by the influence of structural changes in bone on UBPS, rather than changes in bone mineral alone. Prospective studies have to clarify the role of adSOS and UBPS in fracture prediction.

Adult

Measurement of forearm bone mineral density: comparison of precision of five different instruments.

Measurement of bone mineral density (BMD) is used for clinical estimation of fracture risk in osteoporosis. The precision of the method is important for the evaluation of true and clinical relevant changes in BMD in patients with osteoporosis. We measured BMD of the forearm in 14 young, healthy probands (10 males, 4 females), aged 24. 6 +/- 1.5 years with five different instruments using dual-energy X-ray absorptiometry (DXA), single-photon absorptiometry (SPA), and peripheral quantitative computed tomography (pQCT). Precision was expressed as the percentage coefficient of variation (CV%). In addition, the standardized CV% (sCV%) and the root mean square standard deviation (rmsSD%) was calculated for long-term precision. CV% ranged from 1.04 (SPA, distal BMD) to 2.75% (pQCT, trabecular BMD) for short-term precision and from 1.49 (DXA, QDR 1000, 1/3-distal BMD) to 4.33% (SPA, ultradistal) for long-term precision, respectively. The results for the rmsSD% were higher but correlated well with the CV%. A change that exceeds 2 radical2 CV% has been considered as being significant. On this basis, 24.0 +/- 5.1% (mean +/- SEM) of the participants in our study would be expected to have a significant change in BMD without any correlation to the time-delay between the two measurements. Measurements of BMD were done at two locations with all five instruments: ultradistal and middistal BMD using DXA and SPA and total and trabecular BMD using pQCT, respectively. Coefficients of correlation for "between-instrumental" correlation were greater than 0.5 for almost all instruments. Distal and ultradistal BMD measured by SPA and trabecular and total BMD measured by pQCT correlated better with ultradistal BMD measured by DXA. Correspondingly, "within-instrumental" correlation was better for pQCT and SPA than for DXA. The coefficients of correlation between the different DXA methods were greater than 0.95 when corresponding locations were compared. We conclude that the clinical value of monitoring bone loss by measurement of forearm BMD is compromised by the low precision which was seen for DXA methods as well as for SPA and even pQCT in young healthy controls.

Absorptiometry, Photon

Weight-/height-related bone mineral density is not reduced after renal transplantation.

Growth retardation is a frequent finding in patients after renal transplantation (Tx). Areal bone mineral density (BMD) in these patients has usually been reported to be low for age. We investigated the possible influence of height and weight retardation on the measurement of BMD in lumbar spine (BMD(L2-4)) and total body (BMDbody) using dual-energy X-ray absorptiometry in 44 (13 female) pediatric Tx patients with a median age of 13.1 (range 3.3-23.1) years. Patients were studied at 2.9 (range 1-10) years after Tx. Median body height in female and male patients was -2.10 (-3.6 to -0.3) and -2.35 (-5.3 to +1.0) standard deviation score (SDS), respectively. BMD expressed as grams per square centimeter bone area according to age was below the 5th percentile in 10 of 44 patients, but only 1 patient had low values for BMD(L2-4), and none for BMDbody, when the data were corrected for height or weight. BMDbody was closely correlated with height, weight, and body surface area (r=0.88), whereas the correlation for BMD(L2-4) was less (r=0.76). In 6 patients who achieved final height, height SDS was -2.27 (-4.3-0.4). Z-scores for BMDbody related to age, height, and weight were -1.0 (-2.6 to -2.3), 1.25 (0.1-3.4), and 0.81 (0.0-2.4), respectively. There was no age-dependent change when areal BMD values (g/cm2) were corrected for vertebral size to obtain bone volumetric density (BMDvol, g/cm3). Independent of height, cumulative methylprednisolone dose correlated negatively with BMD(L2-4) only in patients who had received a total dose of more than 6 g/m2 of the drug (r = -0.54, P= 0.045). In conclusion, BMD in pediatric patients after Tx is no longer diminished when the data are corrected for height or weight rather than age, or when the data are expressed as bone volumetric density.

Adolescent

Quantitative ultrasonometry (QUS) for the evaluation of osteoporosis risk: reference data for various measurement sites, limitations and application possibilities.

Osteoporosis is a wide-spread disease characterized by low bone mass, deterioration of bone structure and typical fractures, which lead to pain, disability and high costs for health systems. Quantitative Ultrasonometry (QUS) is a new, non-invasive method to study bone density and structure in vivo. This technique has the following advantages: it is safe; it is easy to use, there is no radiation load on the patient, and instruments can be transported and are relatively cheap, as compared with the substantially more expensive methods of traditional osteodensitometry (dual X-ray absorptiometry = DXA, quantitative computed tomography = QCT). For measuring the osteoporosis risk, QUS has the same value as the conventional radiological osteodensitometry methods (QCT, DXA) The combination ofQUS, DXA and QCT improves the message. At present, there are three measurement sites for QUS measurement at the skeleton: the calcaneus, the tibia and the phalanges. The oldest method is the calcaneus measurement, and instruments with and without a water bath are available for this purpose. QUS might be a screening method for osteoporosis. Currently QUS can already be used in clinical practice. It can, for example, be an aid in decision-making for female patients who do not wish to have a postmenopausal hormone replacement therapy (HRT) or who can only barely tolerate doses with a bone-protective effect. In addition, patients can be examined before and after a glucocorticoid therapy with regard to a possible loss in bone mass. As a third possibility, QUS provides a further opportunity for subdividing into development stages patients with an established osteoporosis resulting in fractures, since there is an indication that by means of QUS it may be possible to account for more structural bone changes than with the traditional DXA or QCT methods. Treatment can also be monitored by means of QUS. As prospective studies have shown, increases in SOS by HRT and alendronate and precision error of QUS are lower than expected changes. Due to the greater practicability of QUS (no radiation load, portable instruments), this method ought to be further used in research and clinical settings, and more experience ought to be collected with this method so that wide-ranging experience can help the management of our patients.

Adult

Ultrasound transmission speed and ultrasound bone profile score (UBPS) of the phalanges in normal women and women with osteoporosis.

The distal metaphysis of the first phalanx of the fingers II-V is, like the vertebral body, a useful site for the measurement of mineralisation and structure of the bone because of the simultaneous presence of compact and trabecular bone. With an ultrasound device (DBM sonic 1200, IGEA, Italy), we measured the adSOS (the amplitude dependent speed of sound) and the UBPS (ultrasound bone profile score), a score which is calculated from the graphic traces of the receiving probe with an expert system which uses fuzzy-logic at phalanges II-IV, as well as bone mineral density (BMD) at lumbar spine using dual X-ray absorptiometry (DXA). Precision of the measurements was as follows: adSOS: short-time-CV% = 0.576, long-time-CV% = 1.1, SCV% = 5.9, RMSSD% = 1.825. UBPS: short-time CV% = 5.95. There was no correlation between adSOS or UBPS and lumbar BMD (DXA). There was a significant positive correlation between adSOS and UBPS, r = 0.804 (p<0.00001). The validity of adSOS and UBPS was examined in 25 young and healthy women (mean age: 33.4 year), 15 postmenopausal healthy women (mean age: 58.5 years), 17 women with osteopenia, (mean age: 52.4 years), as defined by a t-score between -1 to -2.5 SD as lumbar BMD (DXA), and 20 women with osteoporosis and vertebral fractures (mean age: 61.4 years). We compared the healthy postmenopausal women and the women with osteoporotic vertebral fractures, the z-score of the adSOS was below minus 1.5 SD and UBPS was below 40, sensitivity was 0.7 for adSOS, and 0.85 for UBPS, with a specificity 0.97 for adSOS, and of 0.93 for UBPS; positive predictive value: adSOS: 0.93, UBPS: 0.85. AdSOS declined with age (r= 0.694, p=0.021); the UBPS was not age dependent (r=-0.15, p = n.s.). The ROC-curve shows a value of 0.96 for adSOS and 0.94 for UBPS. AdSOS and UBPS could discriminate well between the healthy controls and the women with osteopenia or vertebral fractures (p<0.00001). These results show that adSOS and UBPS are precise parameters to be measured at the phalanges. The detection level of pathological changes in osteoporosis are similar between adSOS and lumbar BMD (DXA) and improved by using the UBPS. This might be explained by the influence of structural changes in bone on UBPS, rather than change in bone mineral alone. Prospective studies have to clarify the role of adSOS and UBPS in fracture prediction.

Absorptiometry, Photon

[Measuring bone density with ultrasound--ready for general practice?].

Osteoporosis is characterized by low bone mass, loss of bone structure and/or typical fractures (vertebrae, radius, hip). The costs for the treatment of hip fractures in Germany are about 1 billion DM per year, the mortality rate after hip fractures is between 10 and 30% within the first year. Low bone mass is an important risk factor for the development of fractures; so far however, no procedure for the measurement of bone density has been able to 100 percent differentiate between patients with established osteoporosis and healthy people of the same age. This is due to the fact that the defect in bone structure causing the disease could not be measured so far. Quantitative ultrasonometry (QUS) is a new, non-invasive, radiation-free method for the in vivo measurement of bone density and bone structure. Measurements at the calcaneus and at the phalanxes have shown the equivalence of QUS compared to radiological methods in prospective studies with regard to the prediction of hip fractures. Furthermore it was shown that the beneficial osseous effects of postmenopausal estrogen/gestagen replacement therapy can be detected by QUS. Since QUS is considerably cheaper and the devices are easily transportable, this method is a valuable supplement in the range of diagnostic tools in osteology. Its clinical value however depends on the experience of the user and it should be applied in patients only together with medical history, physical examination and perhaps additional imaging procedures. It was not the inadequate methodology that has brought osteodensitometric methods into discredit but the undifferentiated handling by inexperienced users.

Bone Density

[Bisphosphonate therapy in osteoporosis. Inhibition of trabecular perforation by aminobisphosphonate].

After many years of experience with bisophosphonates in the treatment of "tumor osteopathy" and Paget's disease, these substances have now also been approved for use in the treatment of osteoporosis. Owing to their high affinity for calcium hydroxyapatite, the bisphosphonates are deposited in the bony surface, and the aminobisphosphonates exert their effect at the site of active resorption via direct inhibition of active osteoclasts. As a result of this inhibition of the osteoclastic bone resorption, trabecular perforation is reduced and during the course of bone remodelling by the activity of the osteoblasts, boneformation occurs. In addition to an increase in bone density, both etidronate and alendronate have been shown to inhibit vertebral fractures in patients with osteoporosis. In addition, in patients with preexisting fractures, alendronate is able, at the same time, to lower the incidence of fractures of the femoral neck. With proper administration, the associated occasional gastrointestinal side effects can be avoided. The introduction of bisphosphonates into the treatment of osteoporosis is definitely an enrichment of the therapeutic spectrum in conjunction with the basic treatment comprising calcium, vitamin D, diet and physical measures.

Bone Density

Endocrine function and bone metabolism 5 years after autologous bone marrow/blood-derived progenitor cell transplantation.

BACKGROUND: High dose chemotherapy with or without total body irradiation supported by autologous transplantation of hematopoietic progenitor cells is increasingly being used for hematologic and solid tumors. However, there is only limited information available on late toxicity. METHODS: The authors investigated endocrine function and bone metabolism in 29 patients with a median interval of 5 years after autografting. RESULTS: In accordance with an earlier report on this patient cohort, ovarian failure was observed to be unchanged, except for one woman with recovered ovarian function who gave birth to two healthy children. In two-thirds of the men, follicle-stimulating hormone levels were elevated, suggesting germinal aplasia. Determination of bone mineral density did not reveal osteopenia, despite several risk factors: prolonged immobilization, high dose corticosteroid treatment, and, in women, transient estrogen insufficiency. Frequent impairment of thyroid function has been reported in patients receiving single dose total body irradiation. Overt or subclinical hypothyroidism was not detected, most likely because the total body irradiation was hyperfractionated. CONCLUSIONS: With the exception of gonadal failure, no significant late effects on endocrine function or bone metabolism were observed in this patient cohort.

Adrenocorticotropic Hormone

Ultrasound velocity of the tibia in normal German women and hip fracture patients.

One of the latest developments in quantitative ultrasound (QUS) is the measurement of the speed of sound (SOS) of cortical bone of the midtibia. To determine the diagnostic validity of this method we measured 150 healthy women aged 22-94 years. Additionally, we report on first results of patients with hip fracture. Precision in vivo of the tibial QUS expressed as the percentage coefficient of variation (CV) was 0.39% for the first day and 0.45% after repositioning the second day (mean CV = 0.42%). No significant dependency of tibial SOS was found with weight, height, and body mass index in pre- and postmenopausal women. There was a significant decline of SOS with age in postmenopausal women (SOS = 4225 - 5.3 age, r = -0.46, P < 0. 001), whereas premenopausal women showed no decline (SOS = 3906 + 1. 3 age, r = 0.13, ns) Mean SOS values of premenopausal women were significantly higher than those of postmenopausal women (3960 +/- 78.7 m/second and 3898 +/- 120 m/second, respectively, P < 0.001). Postmenopausal women on estrogen substitution had significantly higher mean tibial SOS values than age-comparable postmenopausal women without estrogen substitution (3980 +/- 99 m/second and 3869 +/- 100 m/second, respectively, P < 0.001). Significant difference between age-matched healthy women, n = 11, and hip fracture patients, n = 13, expressed as z-score of -1.4 SD was found. In conclusion, tibial QUS declines with age and detects higher values in premenopausal women and postmenopausal women on estrogen substitution and lower values in hip fracture patients. Further prospective studies are needed to clarify its role in fracture risk assessment.

Adult

Lower serum 25-hydroxyvitamin D is associated with increased bone resorption markers and lower bone density at the proximal femur in normal females: a population-based study.

Subclinical vitamin D deficiency is considered to be a risk factor for osteoporosis. Therefore, we studied vitamin D status and bone mineral density (BMD) in an age- and sex-stratified population based sample (209 males and 206 females aged between 50 and 80 years). In addition, urinary excretion of pyridinium crosslinks of collagen was determined in order to monitor bone resorption. We found a seasonal variation of serum 25-hydroxyvitamin D (25(OH)D) levels with higher values detected in the summer (27 +/ - 10 ng/ml) and lower values measured in the winter (17 +/- 9 ng/ml). Further analyses were performed separately for winter and summer, respectively. We also excluded subjects taking osteotropic medication. In men, we found no significant relationship between vitamin D status and bone density or pyridinium crosslinks. In women, we found significant positive correlations between 25(OH)D and proximal femur BMD in winter (r = 0.21, p < 0.05) and in summer (r = 0.36, p < 0.01). The association between 25(OH)D and proximal femur BMD persisted after correction for age and body mass index. Serum 25(OH)D and urinary pyridinium crosslinks were inversely correlated in females in winter (r = -0.24, p < 0.02) and in summer (r = -0.32, p < 0.02). Our data support the hypothesis that already moderately low serum levels of 25(OH)D within the "normal" range lead to osteopenia via increased bone resorption.

Age Factors

Relationship between circulating insulin-like growth factor components and sex hormones in a population-based sample of 50- to 80-year-old men and women.

There is a large body of evidence that points to a systemic link between the somatotropic axis and sex hormones, but epidemiologic data on the interactions between the two hormonal systems are still missing. We examined here the associations between the plasma levels of insulin-like growth factor (IGF) I, IGF-II, IGF-binding protein 3 (IGFBP-3), and sex hormones in a population-based sample of 486 men and women, aged 50-80 yr. The strongest association was an age-independent inverse correlation between all three circulating IGF components and sex hormone-binding globulin (SHBG), the major testosterone-binding protein in plasma. Consistent with this, bio-available (non-SHBG-bound) but not total testosterone levels were positively associated with the IGF system in men, and 3 alpha-androstanediol glucuronide was positively correlated with circulating IGFs in women. Moreover, part of the correlation between the circulating IGF system and bone mineral density at the femur and the calcaneus could be accounted for by SHBG. Our data suggest that sex hormones and the GH/IGF system are significantly interrelated in the elderly population. These hormonal interactions may play an important role in human aging and the pathogenesis of age-related diseases.

Aged

Multicenter German reference data base for peripheral quantitative computer tomography.

The wide spread use of bone densitometers in Germany and other European countries has required the establishment of a validated reference population data base. A semianthropomorphic forearm cross-calibration phantom (EFP), developed during a concerted research action of the European Union's programme in Biomedical Engineering (COMAC-BME), was used to cross-calibrate the peripheral quantitative computer tomography (pQCT) devices at four German centers participating in the multicenter study. In total, 723 women and 208 men were included in the normal data base. No significant regional differences were found between the data of the different centers. In addition to the manufacturers calibration standard, proper calibration of the pQCT devices could be monitored during collection of the normal female and male data base. As a merit of the COMAC-BME study the measurements obtained with all pQCT devices thus ensured an uniform reference data base for distal radius measurements in Germany.

Adult

Forearm BMD as measured by peripheral quantitative computed tomography (pQCT) in a German reference population.

Low bone mass as estimated by decreased bone mineral density (BMD) is an established predictor of osteoporotic fractures. One of the latest developments in bone densitometry is peripheral quantitative computed tomography (pQCT) of the forearm. In Germany, the CT bone scanner XCT 900 has already been widely used; however, interpretation of measurements with respect to osteoporosis risk assessment can be improved by better defined and validated reference data. In the present study, this device was used to measure BMD at the distal radius in a well-defined healthy population of 179 German adults (91 men, 88 women) aged 20-79 years. In vivo precision was 1.67% for trabecular and 0.81% for total BMD measurements. Peak values of trabecular and total BMD were observed at the ages 40-50 years in women and 30-40 years in men. Beyond these ages, both trabecular and total BMD showed a linear decline with age, decreasing by 0.85% and 1.08% per year in women and by 0.59% and 0.54% in men, respectively. Measures of BMD were not influenced by weight, height or body mass index (BMI). In both sexes, trabecular and total radial BMD showed a positive and significant correlation with femoral BMD measures obtained by dual X-ray absorptiometry (DXA). Weaker correlations were observed with DXA measures of the lumbar spine. Compared with the 95% reference range provided by the manufacturer, the distribution of age- and sex-specific values of trabecular BMD of the distal radius was shifted to lower values by up to 1 standard deviation.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon

Outcome of bone mineral density in anorexia nervosa patients 11.7 years after first admission.

Osteopenia is a typical finding in patients suffering from anorexia nervosa. Unfortunately, available longitudinal studies are limited by a relatively short follow-up period. Therefore cross-sectional long-term followup studies may help to determine both the outcome of this bone lesion and variables that influence its subsequent development. Of an initial 66 consecutive patients with anorexia nervosa, 51 (77.3%) could be further evaluated. After an average of 11.7 years following first admission, cross-sectional measurements of lumbar and proximal radial bone mineral density (BMD) were performed. The ability to predict BMD using variables obtained from anamnestic and clinical data was then determined by multiple-regression analysis. The BMD of both radial and lumbar bone in anorexic patients with poor disease outcome (as defined by the Morgan-Russell general outcome categories) deviated by -2.18 and -1.73 SD (Z score), respectively. In patients with a good disease outcome lumbar BMD was significantly less reduced compared with radial BMD (-0.26 versus -0.68 SD). Variables reflecting estrogen deficiency and nutritional status in the course of the disease, that is, relative estrogen exposure (for lumbar BMD) and years of anorexia nervosa (for radial BMD), allowed the best prediction of BMD. A marked reduction in cortical and trabecular BMD in anorexic patients with poor disease outcome suggests a higher risk of fractures in these patients. Furthermore, the finding of a persistently reduced cortical and a slightly reduced trabecular BMD, even in patients with good disease outcome, suggests that a recovery of trabecular BMD might be possible, at least in part. Recovery of cortical bone, if possible at all, seems to proceed more slowly.

Absorptiometry, Photon