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M Jergas

Publications and source records attributed to M Jergas.

At least 55 records · Page 3Linked to original sources
PubMed1994

Three quantitative ultrasound parameters reflect bone structure.

We investigated whether quantitative ultrasound (QUS) parameters are associated with bone structure. In an in vitro study on 20 cubes of trabecular bone, we measured broadband ultrasound attenuation (BUA) and two newly defined parameters--ultrasound velocity through bone (UVB) and ultrasound attenuation in bone (UAB). Bone mineral density (BMD) was measured by dual X-ray absorptiometry (DXA) and bone structure was assessed by microcomputed tomography (microCT) with approximately 80 microns spatial resolution. We found all three QUS parameters to be significantly associated with bone structure independently of BMD. UVB was largely influenced by trabecular separation, UAB by connectivity, and BUA by a combination of both. For a one standard deviation (SD) increase in UVB, a decrease in trabecular separation of 1.2 SD was required compared with a 1.4 SD increase in BMD for the same effect. A 1.0 SD increase in UAB required a reduction in connectivity of 1.4 SD. Multivariate models of QUS versus BMD combined with bone structure parameters showed squared correlation coefficients of r2 = 0.70-0.85 for UVB, r2 = 0.27-0.56 for UAB, and r2 = 0.30-0.68 for BUA compared with r2 = 0.18-0.58 for UVB, r2 < 0.26 for UAB and r2 < 0.13 for BUA for models including BMD alone. QUS thus reflects bone structure, and a combined analysis of QUS and BMD will allow for a more comprehensive assessment of skeletal status than either method alone.

Absorptiometry, Photon↗
PubMed1994

Gastrointestinal transit through esophagus, stomach, small and large intestine in patients with progressive systemic sclerosis.

Liquid esophageal transit and gastric emptying, mouth-to-cecum transit, and whole gut transit of a solid-liquid meal were measured in 14 patients with PSS, 16 control subjects (esophageal transit), and 20 control subjects (gastrointestinal transit), respectively, by using scintigraphic techniques, the hydrogen breath test, and stool markers. In patients with PSS, the glucose hydrogen breath test for detection of small intestinal overgrowth was performed and various gastrointestinal symptoms were determined. Esophageal transit and gastric emptying were significantly prolonged in PSS patients with 11 of 14 PSS patients (79%) disclosing delayed esophageal transit and eight of 14 PSS patients (57%) disclosing delayed gastric emptying. All PSS patients with prolonged gastric emptying also had delayed esophageal transit and there was a significant positive correlation between esophageal transit and gastric emptying (r = 0.696, P < 0.01). No significant differences between PSS patients and controls were detected concerning mouth-to-cecum transit and whole gut transit, but abnormally delayed mouth-to-cecum transit was found in four of 10 PSS patients (40%) and abnormally prolonged whole gut transit was detected in three of 13 PSS patients (23%). Small bacterial overgrowth was diagnosed in three of 14 PSS patients (21%). Delayed esophageal transit and gastric emptying were associated with dysphagia, retrosternal pain, and epigastric fullness, while prolonged whole gut transit was associated with constipation. It is concluded that delayed gastric emptying is frequently associated with esophageal transit disorders in PSS patients and may be one important factor for the development of gastroesophageal reflux disease in these patients.

Adult↗
PubMed1994

[High resolution computerized tomography of the temporal bone in mandibulofacial dysostosis].

High resolution CT (HR-CT) scanning of the temporal bone was performed in three patients with a fully expressed mandibulofacial dysostosis for preoperative assessment of temporal bone abnormalities. The external auditory canal was absent in five of six ears. Scans revealed a dysplastic middle ear cleft with dysplastic and partly dislocated ossicles. The ossicles were absent in two temporal bones. In no patient was the mastoid bone pneumatised. The inner ear was affected in only one patient in whom a shortening of the lateral semicircular canal could be found bilaterally. The role of HR-CT of the temporal bone as a preoperative diagnostic tool for the assessment of abnormalities of surgical import is discussed.

Adult↗
PubMed1994

[Effect of site and width of stomach tube after esophageal resection on gastric emptying].

The gastric emptying of a mixed solid-liquid meal labeled with 99 mTc was evaluated in 14 healthy volunteers and in 14 subjects after esophageal replacement. The stomach had been placed seven times in the posterior mediastinum and seven times behind the sternum. The rate of emptying was measured by an anterior gamma-camera technique. Furthermore, the width of the esophageal substitutes was determined by CT-scans. The intrathoracic stomach displayed a prolonged emptying rate, independent of its location in the anterior or posterior mediastinum. Interestingly the width of the stomach influenced the discharge of the test-meal, whereby the more narrow the substitute the faster the emptying rate.

Adenocarcinoma↗
PubMed1993

[Correlation between hyperplastic and adenomatous polyps of the colon].

PROBLEM: Although hyperplastic polyps are considered to be non-neoplastic, they nevertheless have a number of characteristics in common with adenomatous polyps. STUDY DESIGN: Since hyperplastic polyps and adenomas frequently occur together, the question arises as to whether hyperplastic polyps, found for example during sigmoidoscopy, might not be an indicator of possibly neoplastic polyps in the more proximal part of the bowel. In a retrospective analysis of first-time total colonoscopies in 685 patients, we investigated the relationship between hyperplastic and adenomatous polyps. RESULTS: Twenty-one patients proved to have only hyperplastic polyps in the rectosigmoid, while 12 of these patients (11.8%) also had adenomatous polyps in the more proximal parts of the colon. In contrast, 30.8% of the patients (n = 109) with rectosigmoidal adenomas also had adenomas in the more proximal colon. Irrespective of histology, as the size of rectosigmoidal polyps increased, so did the percentage of patients with adenomas in the proximal colon--from 22.4% in the case of small polyps not exceeding 5 mm in diameter to more than 31.2% in the case of polyps larger than 5 mm in diameter. When both hyperplastic and adenomatous polyps appeared together, hyperplastic polyps were found in larger numbers in the same or anatomically adjacent segment of the colon. CONCLUSION: The results of this study suggest that the presence of hyperplastic polyps in the rectosigmoid is not associated with an increase in the incidence of proximal adenomas, while rectosigmoidal adenomas must be considered indicators of adenomas in the more proximal parts of the bowel.

Adenomatous Polyposis Coli↗
PubMed1993

[Ultrasound procedure in the diagnosis of osteoporosis].

Ultrasound transmission velocity and ultrasound attenuation of the appendicular skeleton are influenced by bone density and by bone structure and correlated to mechanical properties of bone. This article reviews basic principles of these techniques and their experimental and clinical applications. Results of the ultrasound techniques and their relation to established radiological measurements for the assessment of bone mineral density in vivo and in vitro are reported. Factors with an influence on both ultrasound transmission velocity and ultrasound attenuation are discussed. Ultrasonic measurements of the bone may offer a simple, non-invasive and radiation-free assessment of bone quality in osteoporosis and other metabolic diseases affecting the bone. However, further studies are required to confirm this.

Aged↗
PubMed1993

[Ultrasound velocity measurement in the diagnosis of postmenopausal osteoporosis].

We evaluated ultrasound transmission velocity as an indicator for osteoporosis at the os calcis of both feet and at the proximal phalanges of DII and DIII of both hands in 74 female subjects (22 premenopausal, 29 postmenopausal non-osteoporotic and 23 postmenopausal osteoporotic). In addition dual x-ray absorptiometry (DXA) of the lumbar spine was performed in 30 women and a combined cortical thickness index (CCT-index) of os metacarpale II was calculated from hand radiographs in 29 women. Ultrasound velocity at all sites slightly decreased in premenopausal women with age and declined significantly after menopause. At the hand postmenopausal osteoporotic women had significantly lower velocities than normal postmenopausal or premenopausal women while no difference could be seen at os calcis. An only poor or moderate correlation between ultrasound velocity at all sites and DXA of the lumbar spine and a good correlation between the CCT-index and velocity at the fingers indicate that ultrasound velocity is not only affected by bone density but even more by structural properties.

Absorptiometry, Photon↗
PubMed1993

[Fixateur interne: a comparative biomechanical study of various systems].

The three-dimensional stability provided by three spinal fixation devices of the type "fixateur interne" have been studied in an in vitro model using L2-L4 sections of the lumbar spine. Three-dimensional rotations and translations for the intact and instrumented spine under physiological loads in flexion/extension, lateral bending, and axial rotation were determined. To objectify the results, a dimensionless related stability parameter was introduced. The tested devices were: Dick (AO-Synthes), Kluger (Endotec), and SOCON (Aesculap). In addition a vertebrectomy L3 was performed to simulate a severe fracture model. Different screw diameters allowed for a direct comparison of two internal fixateur systems on identical specimens. In contrast to the intact spine, the instrumented spine reflects purely linear structural behaviour with a stabilization significant in flexion/extension and lateral bending and only moderate in axial rotation. Differences for various systems tested were found to be small. The results for the fracture model confirmed the efficiency of these internal fixation devices.

Biomechanical Phenomena↗
PubMed1993

[Effect of soft tissue injuries on the biomechanics of sagittally symmetric thoracolumbar vertebral compression fractures].

Thoracolumbar compression-fractures were performed in an in-vitro model with a deformity of 9.7 degrees and 12.3 degrees. After stabilisation of the fracture additional soft tissue injuries were carried out by dissection of the posterior ligaments and ruptures of the nucleus and annulus of the intervertebral disc. The disc injuries led to a significant instability. The degree of kyphotic deformation showed the most distinct influence on torsion with an increase in range of motion of 64% (9.7 degrees) versus 181% (12.3 degrees).

Biomechanical Phenomena↗
PubMed1993

Radiologic diagnosis of osteoporosis. Current methods and perspectives.

Osteoporosis is defined as a decrease in bone mass accompanied by structural changes, leading to an increase in fracture propensity. Early diagnosis of osteoporosis, fracture risk prediction, and assessment of efficacy of therapy therefore are of great interest. A number of noninvasive techniques are available for measuring bone mass at multiple sites of the skeleton. This article reviews basic methodology and developments in radiology such as x-ray and photon absorptiometry and quantitative computed tomography, which are routinely used in clinical practice. Recent techniques for assessment of bone mineral density and structure, such as ultrasound measurements, and their possible clinical applications also are discussed.

Absorptiometry, Photon↗
PubMed1993

[Advances in the diagnosis of osteoporosis].

Bone densitometry allows for an assessment of osteoporotic fracture risk. Well-established methods include dual X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and single X-ray absorptiometry (SXA). The advantages and disadvantages of these methods are discussed. Promising innovative techniques include three new X-ray-based approaches: lateral DXA and peripheral QCT for the determination of bone mineral density of the spine and radius, respectively, and morphometric X-ray absorptiometry (MXA) for computerized quantification of vertebral deformities. Quantitative ultrasound (QUS) and quantitative magnetic resonance (QMR), on the other hand, open up new ways of assessing bone microarchitecture in addition to bone mineral density--without the use of ionizing radiation. These new approaches promise to yield new information on skeletal status. Complementing existing bone densitometry approaches, this may improve fracture risk assessment.

Absorptiometry, Photon↗
PubMed1992

[Ultrasonic velocity measurements at weight-bearing and non-weight-bearing sites of the peripheral skeleton. The effect of physical activity in soccer players].

Ultrasound transmission velocity at the appendicular skeleton is determined by elastic properties of the bone as mass density. We evaluated ultrasound transmission velocity at the os calcis of both feet and at the proximal phalanges of DII and DIII of both hands in 51 male subjects. 28 of them were professional soccer players of the 1st German division, 11 subjects performed non-professional exercise in various athletic organisations regularly and 12 did not exercise at all. A significant difference in the speed of sound could be seen at os calcis, where the soccer players had higher velocities than the other groups. The differences between the groups at the upper and lower extremities suggest that changes in ultrasound transmission velocity are not only affected by structural changes in the aging skeleton, as it might be suggested by age differences, but by exercise. Physical exercise can change the properties (structure and/or density) of weightbearing bone and this can be detected by measuring ultrasound velocity.

Adolescent↗
PubMed1992

[Product of the month: scientific text processing using the MS-DOS computer].

A new German word processing system, "Starwriter 6.0" for MS-DOS computers is introduced and important functions are described. The possibility of using different fonts, creating complex formulas, footnotes and endnotes, and using various functions for importing and exporting text and data files make this program highly suitable for scientific texts.

Germany↗
PubMed1992

[Radiologic diagnosis of osteoporosis. Current methods and outlook].

Osteoporosis is defined as a decrease in bone mass and structural changes in bone leading to an increase in fractures. Early diagnosis as quantification of prophylaxis and treatment are of great interest. A number of non-invasive techniques are available for measuring bone mass at multiple sites of the skeleton. This article reviews basic methodology and developments in radiography as in x-ray or gamma photon absorptiometry, quantitative computed tomography, ultrasound velocity and attenuation and magnetic resonance imaging. Clinical applications of these methods are discussed. The still experimental use of ultrasound and MRI in assessment of bone-mineral content may also give information on bone quality.

Absorptiometry, Photon↗