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G Seidl

Publications and source records attributed to G Seidl.

At least 19 recordsLinked to original sources
PubMed2001

A comparison of quantitative computed tomography and dual X-ray absorptiometry for evaluation of bone mineral density in patients on chronic hemodialysis.

Chronic renal failure leads to a reduction of bone mineral density (BMD). Therefore, noninvasive methods to evaluate BMD are also used regularly in this patient population. In this study, we compared the results of two widely used methods, quantitative computed tomography (QCT) of the lumbar spine and dual x-ray absorptiometry (DXA) at different sites in 90 patients on chronic hemodialysis. Additionally, we also determined various clinical and biochemical data to assess their relationship to BMD at the different measurement sites. A total of 75% of our patients was found to have reduced BMD, and 25% had an average z-score below -2. Z-scores obtained by the different methods and at the different measurement sites within an individual patient varied considerably from completely normal to severely reduced values. Multivariate analyses using clinical and biochemical parameters showed lower values of BMD at all measurement sites after transplantation and marginally higher values after parathyroidectomy, which was seen only in DXA measurement at the femoral neck. We conclude from our study that determination of BMD in chronic hemodialysis patients yields highly variable results, depending on the technique used. As long as the exact clinical relevance of these results has not been determined, regular routine measurement of isolated sites of BMD cannot be advocated in this patient population.

Absorptiometry, Photon↗
PubMed1998

Inhibition of Fc epsilon RI-mediated activation of mast cells by 2,3,4-trihydropyrimidino[2,1-a]isoquinolines.

Assays based on reporter gene technology represent today an important tool in the pharmaceutical industry for discovering novel compound classes interfering with the activation and signaling of target cells after stimulation. Here we describe a reporter gene assay targeting mast cell activation of IgE plus antigen, established in an attempt to identify substances preventing type I allergy (allergic rhinitis, allergic conjunctivitis, allergic asthma, and acute and chronic urticaria). The assay is based on a murine mast cell line designated CPII, stimulation by IgE plus antigen, and a reporter gene construct with the TNF alpha promoter linked to luciferase as a read-out system. Via screening about 50,000 substances, compound 2 was found to inhibit the reporter gene induction in the submicromolar range in this assay. Analogues of compound 2 of the 2,3,4-trihydropyrimidino[2,1-a]isoquinoline type were synthesized starting from 2-alkyl-substituted benzonitriles via aminolysis with 1,3-diaminopropane, dimetalation of 2-substituted 2-phenyl-1,4,5,6-tetrahydropyrimidines with n- and sec-butylithium, reaction with carboxylic acid methyl esters, and finally acidic dehydration. From about 50 derivatives, compound 41 was selected as a lead structure with an IC50 of 0.2 microM and a TC50 of 2.7 microM. In a first profiling in secondary assays, it effectively interfered with the production of mediators such as TNF alpha, IL-4, IL-6, IL-13, and leukotriene synthesis as measured by the corresponding ELISAs. In addition, a passive cutaneous anaphylaxis in mice (a typical type I reaction) is inhibited to more than 90% by compound 41, when administered intradermally 90 min before challenge.

Animals↗
PubMed1998

High turnover bone disease following lung transplantation.

Recipients of lung transplants are at very high risk for significant bone loss. Nevertheless, data on bone disease after lung transplantation are still limited. We, therefore, retrospectively evaluated the data of 33 patients surviving at least 1 year after lung transplantation (LTx) who were seen in our outpatient clinic for osteologic evaluation. Results of clinical evaluations, radiographs, and dual-energy X-ray absorptiometry (DXA) were related to each other, to clinical variables, and to serum levels of osteocalcin, parathyroid hormone (PTH), and 25-hydroxyvitamin D: 14 of 33 patients (42%) had vertebral fractures, 9 of whom were diagnosed within 2 years after transplantation. Bone mineral density values (DXA) were markedly decreased and predictive of compression fractures. 25-Hydroxyvitamin D levels were low in 13 patients (39%) and PTH was elevated in 7 (21%). Despite corticosteroids and low 25-hydroxyvitamin D, serum osteocalcin was elevated in 12 patients (36%). This was only partially explained by hyperparathyroidism, low sex hormones, and impaired renal function, and may partly be caused by cyclosporin A. We thus conclude that severe symptomatic bone disease is common in lung transplant recipients and due to a complex situation including high turnover bone loss and hypovitaminosis D. DXA can be used to estimate fracture risk for individual patients.

Absorptiometry, Photon↗
PubMed1997

Impact of spinal degenerative changes on the evaluation of bone mineral density with dual energy X-ray absorptiometry (DXA).

The purpose of this study is to evaluate degenerative factors in a postmenopausal patient group and differentiate the influence on bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DXA). The patients and methods included an investigation of 144 postmenopausal women (mean 63.3 years) with PA-DXA of the spine. Degenerative factors (osteophytes, osteochondrosis, scoliosis, and vascular calcification) were evaluated from plain lumbar radiographs, their estimated probability was analyzed as a function of age, and their influence on BMD measured by PA-DXA was determined. The results of the study revealed osteophytes in 45.8%, vascular calcifications in 24.3%, scoliosis in 22.2%, osteochondrosis in 21.5%. The estimated probability for degenerative factors increased from 35 to 80% in the 55- to 70- year age group. Osteophytes and osteochondrosis were associated with up to a 14% increase in BMD values (P < 0.001). Vascular calcifications showed a positive trend, whereas scoliosis did not show a discernible influence.We concluded that degenerative factors, except for scoliosis, showed an influence on BMD as measured by DXA. Their prevalence increased rapidly between 55 and 70 years of age. Interpretation of PA-DXA spine data for subjects of or above this age range should be complemented by plain film radiographs.

Absorptiometry, Photon↗
PubMed1997

Imaging of tendons--adaptation, degeneration, rupture.

Tendon imaging is mainly performed with ultrasonography (US) and magnetic resonance imaging (MRI) and has been improved within the last years because of technical advancements and a better understanding of tendon pathology. Several concepts concerning the etiology and the course of tendon diseases have influenced image interpretation and vice versa. Adaptive mechanisms within the tendon tissue against stress can be observed mainly on histologic specimens and not macroscopically or with in-vivo imaging. Degeneration may occur in the form of tendinitis, peritendinitis, enthesitis, or myotendinal junction abnormality. Distinct imaging findings exist for most of these forms. Many concepts that have been developed to explain tendon degeneration have been applied on virtually all tendons in the human body. They can be grouped into those which focus on hypovascularization, on biomechanical overload, and on degeneration secondary to other underlying disease. Tendon rupture seems, in many cases, to be the final stage of tendinitis. From this point of view, imaging may be used to predict the risk of tendon rupture together with other intrinsic and with extrinsic parameters. These considerations result in the concept of the "vulnerable zone" and of the "critical phase" in which tendon ruptures may predominantly occur.

Adaptation, Physiological↗
PubMed1996

Recorticalization after bifocal internal bone transport in the double-plated sheep femur.

Distraction osteogenesis and bone remodelling after the end of bone transport were investigated in one femur each of six adult male sheep. A newly designed internal distraction device was used. A custom-made osteosynthesis plate was fixed on the lateral side of the femur, and two transporting plates driven by a transcutaneously inserted screwdriver moved two bone cylinders simultaneously over a 40 mm defect. An additional plate was applied ventrally to stabilize the device. Bone transport was begun 2 weeks postoperatively at 1 mm/day at each transporting plate until they came into contact. New bone formation within the distraction gaps was evaluated by computed tomography scans and was quantified at 4 and 6 months by dual energy x-ray absorptiometry as well as histomorphometry on polyfluorochrome-labelled undecalcified ground sections and microradiographs. At 4 months, all distraction gaps were bridged by abundant newly formed bone trabeculae, which were reduced and condensed to cortex-like layers of new bone at 6 months. Less new bone was always found under the lateral device than in the unplated medical and dorsal segments, but the amount of new bone under the ventral plate was comparable with that in the unplated regions. The results of this pilot study show that distraction osteogenesis can be achieved with an internal device such as this one and that recorticalization and restoration of a medullary canal occur despite the relatively rigid internal stabilization by the plates.

Animals↗
PubMed1996

[MR imaging in gout].

The appearance of gouty tophus in magnetic resonance imaging (MRI) is characteristic. On T1- and T2-weighted SE images, the signal intensity of tophaceous lesions is similar to that of muscles. According to the histology, T2-weighted SE images demonstrate extremely hyperintense signals, which reflect the high protein content in the amorphous center of the tophus. The microscopic urate crystals deposited there have no MRI signal and are of no further diagnostic impact. Vascularized granulation tissue surrounding the tophus center enhance after intervenous application of contrast agents (Gadolinium). The inflamed tophus is associated with local edema, causing high signal intensity. MRI is superior to plain radiography for early detection of intraosseous tophi. Involvement of anatomical structures such as ligaments and tendons can be evaluated sufficiently. For peripheral joints, axial slice orientation is most helpful.

Adult↗
PubMed1996

[Ultrasound morphology of the Achilles tendon and differential diagnosis].

AIM: To correlate sonographic findings and clinical disorders of the Achilles tendon, considering newer aspects of their etiology and pathogenesis. METHOD: In a retrospective cross-sectional study the sonographic findings in 52 patients with tendonitis, heel swelling, or suspected rupture were analysed and correlated with the final diagnosis. Tendon lesions due to lipid storage diseases or rheumatic diseases were analysed on the basis of reports in the literature. RESULTS: Ultrasound abnormalities were found in 41 of the 52 symptomatic patients (40 degenerative changes of the tendon and/or the peritendinous tissue, 1 inflammatory rheumatologic process, 1 metabolic disorder, 8 ruptures, 2 congenital or developmental abnormalities). Ultrasound signs were not specific for each of the diagnoses but typical combinations of distinctive signs together with clinical findings led to the correct diagnoses. CONCLUSION: Patients with suspected lesions of the Achilles tendon should undergo an ultrasound investigation both to promote the exact diagnosis and to define the extent of the disease.

Achilles Tendon↗
PubMed1996

MRI in assessment of the systemic manifestations of rheumatological disease.

Magnetic resonance imaging (MRI) has emerged as complementary imaging modality to conventional radiography. The same diagnostic rules that are used in the interpretation of the routine radiographs should be applied to the analysis of MR images with the macroscopic spread of the disease as a main diagnostic clue. MRI has been shown to be a sensitive tool in detecting early arthritic changes and erosions, inflammation in periarticular tendons and tendon sheaths, and in juxtaarticular bursae. MRI plays a pivotal role in diagnosis of arthritis of the craniocervical junction and its complications. It also has been used effectively to detect insufficiency fractures and osteonecrosis. MRI may be important in diagnosing early arthritis, in specifying the differential diagnosis of rheumatic disease, and in selecting subgroups of patients to provide tailored therapeutic regimens.

Arthritis, Rheumatoid↗
PubMed1995

Effect of bone cylinder length on distraction osteogenesis in the rabbit tibia.

The viability and osteogenic potential of bone cylinders for bone transport was investigated in one tibia of 18 mature male New Zealand rabbits. The length of the bone cylinder was equal to or twice that of the diameter of the tibia. The cylinder was cut subperiosteally with an externally cooled oscillating saw from a lateral approach, after a specific unilateral external fixator had been applied. To simulate bone transport, one end of the cylinder was fixed to the distal bone stump by a cerclage wire and healing and revascularization was prevented by an interposed expanded polytetrafluoroethylene membrane. The periosteum was re-adapted and sutured, and distraction began 10 days postoperatively at 0.25 mm/12 hours for 22 days. New bone formation in the distraction gap was quantified by dual energy x-ray absorptiometry and by computer-assisted histomorphometry of polyfluorochrome-labeled undecalcified bone sections and corresponding microradiographs. In half of the animals with each size cylinder, osseous bridging occurred, so the findings on distraction osteogenesis are reported only for the remaining nine animals. Generally, centripetal mineralization of the gap with two distinct zones of ripening bone structures and a central radiolucent fibrocartilaginous zone could be distinguished. Neither absorptiometry nor histomorphometry showed significant differences in the overall amount of this new bone formation for the bone cylinders of two different lengths. However, osteogenesis was significantly greater at the proximal end than at the cylinder. New bone was formed predominantly from endosteal sites in the smaller cylinders and from periosteal sites in the larger cylinders. Histologically, there was complete necrosis of both sizes of cylinders, followed by revitalization through newly formed vascular channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

[Nutrition and osteoporosis: a nutritional analysis of women in postmenopause].

In a cross-sectional study the effects of several nutritional factors on the manifestations of osteoporosis were investigated in 23 postmenopausal women aged 50 to 70 years. Twelve women (group 1) with osteoporosis and eleven healthy control subjects (group 2) were instructed to keep a seven-day nutritional record. Body mass index (BMI) was recorded, and radiological and bone mineral density investigations were undertaken. The daily total energy, protein, fat, carbohydrate, fiber, oxalic acid, calcium, magnesium, phosphorus, sodium, fluoride, zinc, copper, manganese, vitamin C, D, and K intake were analysed within the framework of a nutritional science program. No intergroup differences were observed with regard to total energy intake, nutritional components and BMI; however, age and years since the menopause differed significantly (p < 0.05). The results suggest that the manifestation of osteoporosis in women is influenced to a greater extent by age and years since the menopause than by the distribution of nutritional factors in a normal mixed diet. However, further studies are essential to evaluate the role of dietary composition on the manifestations of osteoporosis.

Age Factors↗
PubMed1995

[Ultrasound diagnosis of the popliteal fossa].

Sonography of the knee is a well-established method for the diagnosis of palpable tumors. However, evaluation of the menisci, cruciate ligaments, and hyaline cartilage is controversial. Despite the variable echogenicity and extension of different diseases, many distinct sonographic signs are different in cysts, solid neoplasms, and vascular diseases. The investigator must be familiar with various patterns of popliteal cyst formation: crescent-shaped, cross-shaped, slitlike, and grape-like cysts. Because of diagnostic and economic reasons the following concept should provide guidance when diagnosing lesions of the popliteal fossa: the first step of diagnostic imaging should include plain film radiography and sonography. In a second step MRI and/or arthroscopy should be performed.

Aneurysm↗
PubMed1993

Ultrasonography of the Achilles tendon in hypercholesterolemia.

The ultrasonographic (US) appearance of Achilles tendon was examined in 34 patients with hypercholesterolemia (10 with familial (FH), and 24 with secondary hypercholesterolemia (SH)), and in 22 patients with normal tendons. US findings were compared with clinical, laboratory, and radiologic results. In patients with FH, typical xanthomas in the form of hyperechoic tendinal tumors were found in only 15% while various forms of inhomogeneity of tendon structure without xanthoma formation were found in 75%. The high rate of tendon inhomogeneity may be due to the concomitant occurrence of both xanthomas and degeneration of tendon fibers. Physical examination revealed abnormalities in 60% of these patients. At CT of the tendons, abnormalities were found in 65% of the FH patients and in 40%, abnormalities were shown by plain radiography. In SH, the results did not differ significantly from normal controls. In our opinion US should be used to prove or rule out Achilles tendon abnormalities in patients with FH for prophylaxis and treatment of tendinitis and tendon rupture.

Achilles Tendon↗
PubMed1993

[Systematic strength training in the postmenopause: accompanying densitometric control with DXA].

Of all the forms of osteoporosis, the postmenopausal type is the most important in social medicine due to the potentially high fracture risk in aging. The positive effects of physical activity on bone density have been emphasized in several studies. In this study on 31 female volunteers (minimum age 50 years), who had been postmenopausal for at least 2 years, 16 underwent systematic strength building (training group). They were compared with a control group consisting of 15 female volunteers. The parameters of success were physical strength and bone mineral density (BMD) before and after training. BMD was measured by dual-energy X-ray absorptiometry. The subjects in the control group showed significant decrease in bone density after 6 months: between 6.7 and 22.3% of the values measured at the beginning. The loss was more evident in the proximal femur than in the lumbar spine. In contrast, the subjects in the training group only showed a marginal decrease in bone density in the proximal femur: 0.8 to 3.8% of the earlier values. In the lumbar spine there was even a slight increase (+0.3%) in bone density.

Absorptiometry, Photon↗
PubMed1993

[Bone density of the lumbar spine and femur in acromegaly].

Acromegaly is regarded as a cause for secondary osteoporosis, whereas recent papers suggest that growth hormone increases bone mineral density (BMD). In 16 patients with active acromegaly we found an increased BMD compared to normal controls in the lumbar spine and the proximal femur by means of dual energy X-ray absorptiometry. This increase in BMD was statistically significant in the femoral neck and in Ward's triangle (P = 0.05). Moreover, no signs of osteoporosis were found radiologically.

Absorptiometry, Photon↗
PubMed1992

[Sonographic structural analysis of the Achilles tendon and biomechanical implications].

Ruptures of the Achilles tendon mainly occur on the ground of predisposing destruction of tendon structure. The aim of this retrospective US study was to evaluate the location and extent of tendon abnormalities. 62 patients (49 male, 13 female; 19 to 57 years, mean 38) with achillodynia of short duration and/or clinically suspected tendon abnormalities were evaluated sonographically. Together with a review of the literature, US findings (location, extent, and echo pattern) were compared with clinical findings. With US, abnormalities could be detected with a sensitivity of 0,76 and a specificity of 0.9. Pathologic lesions could be grouped as follows: (1) pain without any clinical signs or US findings (tenalgia); (2) nodular tendinitis which in 52% appeared in the form of a tiny hypoechoic lesion in the ventromedial part of the tendon 2-3 cm proximal to the os calcis; (3) peritendinal oedema; (4) circumscribed tendon swelling, (5) extensive inhomogeneities of tendon structure. With US, abnormalities of the Achilles tendon may be detected at an early stage of the disease and hence the risk of tendon rupture may be predicted to better advantage.

Achilles Tendon↗
PubMed1992

[Renal osteodystrophy: the spectrum of the x-ray symptoms in modern forms of kidney transplantation and long-term dialysis therapy].

Plain film radiography and microradioscopy represent standard imaging for diagnosis and grading of renal osteodystrophy. The aim of this retrospective study was to evaluate the effects of modern therapeutic regimens on skeletal abnormalities as diagnosed radiographically. 198 patients were investigated. X-ray findings of 38 patients from 1981-1983 (16-66 years, 40.1 +/- 13.4; 23 male, 15 female) were compared with those of 160 patients from 1991 (20-71 years, 48.4 +/- 12.5; 98 male, 62 female). We found significant differences in respect of the spectrum and the degree of skeletal abnormalities. The prevalence of phalangeal resorptions lowered from 87 to 50%, the prevalence of soft tissue calcification from 68 to 57%. Therefore, renal osteodystrophy is not as extensive as it was ten years ago, but it still continues to be an unavoidable complication of renal insufficiency.

Adolescent↗