Biomedical subjects
Publications and source records attributed to M Jäger.
A report was made on a 25 year old patient with a penetrating heart injury with basic diagnosis, and treatment. A successful management was a result of good performance of the resuscitation chain, exactness of the clinical diagnosis and interdisciplinary cooperation between surgeons and anaesthetists.
The health consequences of long-term professional activity in loading for transport were investigated in an epidemiological study. This involved determining the frequency of orthopedic diseases within a series of transport workers and comparing it with the disease frequency in a comparable group with the same age distribution. The frequency of orthopedic diseases in transport workers is about 22% higher than in the other group. Most of the findings relate to the lower lumbar spine. An increase in the number of diseases can be observed in the transport workers even after a short period of professional activity. In order to examine the possible cause for the increased frequency of disease, the load on the lower lumbar spine was determined quantitatively using biomechanical model calculations. A three-dimensional biomechanical model that allows examination of both static and dynamic load was developed for this purpose. The influence of posture, the mass of the load to be transferred, and the acceleration of the load and the body on the mechanical spinal load were examined as typical examples of load manipulation. In the assessment of load, the compressive forces calculated were compared with the strength of the spinal elements. The compression forces on the lower lumbar spine are of the same order of magnitude as the strength. The high mechanical load can therefore be regarded as a possible cause of the high frequency of disease among persons whose professional activity involves lifting heavy loads.
A dynamic biomechanical human model is presented which allows the quantification of mechanical parameters such as torque, compressive and shear forces, and pressure at the lumbar intervertebral discs. The human model comprises a total of 19 body segments. Various trunk flexions can be analysed due to the provision of 5 joints at the level of the 5 lumbar intervertebral discs. The influence of intraabdominal pressure on spinal load is considered. The inclusion of the influences of gravity and inertia permits the analysis of both static body postures and dynamic body movements. Since the model is 3-dimensional, the lumbar stress can be calculated during both symmetrical tasks in the median sagittal plane as well as during non-symmetrical ones. The influences on spinal stress of trunk inclination and the position of an external load relative to the body are quantified for various load weights up to 50 kg. The torque at the lumbo-sacral joint L5-S1 lies, dependent on posture and load lever-arm, within the range between 0 and 500 Nm; the compressive force on L5-S1 lies within the range between 0.4 and 10 kN, and the shear force at L5-S1 between 0.2 and 0.9 kN. The influences of lift velocity and jerky movement on lumbar stress are quantified. Simulated humpback and hollow-back postures are studied. The compressive forces at the 5 lumbar intervertebral discs are compared. The validity of the model is examined by comparing the model calculations with the intradiscal pressure measurements taken from the literature. Strength tests on lumbar intervertebral discs and vertebrae are collated from the literature in order to assess the lumbar stress during load lifting. The lumbar ultimate compression strength varies within a wide range. The mean value for a total of 307 lumbar segments amounts to 4.4 kN, the standard deviation to 1.9 kN. In conclusion, lumbar compressive force values during lifting fall within the same range as the strength values for the human lumbar spine.
Material handling tasks result in high load on the skeletal system. Long-term employment in transportation jobs may therefore cause a high frequency of orthopaedic diseases, particularly in the spinal region. An epidemiological study was performed on employees from a large company in order to test this hypothesis. The medical history of 249 male transport workers was examined by means of statistical analysis of the orthopaedic diseases documented in the record file of their company's health service. For purposes of comparison, the same data evaluation was performed for an age-matched reference group consisting of 267 persons chosen randomly from among the male employees in the same company. The proportion of persons with orthopaedic diseases amounts to 77.1% among the transport workers and 62.9% among the reference persons. It is consequently 1.22 times higher for the transport workers than for the reference persons ("rate ratio RR" = 1.22). The greatest part of all orthopaedic diseases affects the spine. Within the spine, the lumbar region is the most frequently damaged. Both for the totality of all spinal sections as well as for diseases of particular spinal sections (cervical, thoracic, lumbar spine), the proportion of the transport workers with diseases is higher than that of the reference persons (RR between 1.20 and 1.36). The proportion of persons with spinal diseases increases with age in both groups. There is no observable difference between the groups with regard to the frequency of persons with degenerative diseases.(ABSTRACT TRUNCATED AT 250 WORDS)
The effects of chronic oral treatment of rats with 400 mg/kg body weight camostat, a synthetic protease inhibitor, on weight gain and both pancreatic exocrine and endocrine secretion were studied and compared with pair-fed controls. Administration of camostat was found to result in a lower weight gain than in untreated rats fed ad libitum because of reduced food intake. The pancreas of treated rats showed hypertrophy and hyperplasia with significantly higher total contents of amylase, lipase, trypsinogen and chymotrypsinogen than that of pair-fed controls. The specific activity of lipase, trypsinogen and chymotrypsinogen remained unchanged but the specific activity of amylase was significantly lower than in pair-fed controls. Stimulation of pancreatic enzymes with CCK 8 in treated rats resulted in a greater output of proteases, no difference in secretion of lipase and a lower secretion of amylase than in pair-fed rats. Glucose-dependent insulin secretion was also significantly lower in camostat-treated rats than in controls. This effect could be reversed by gastric inhibitory polypeptide. After termination of treatment with camostat all enzymes were normalized within 14 d. Our results on the hypertrophied pancreas of rats suggest preferential synthesis and secretion of protease at the expense of amylase and diminished sensitivity of insulin to stimulation by glucose. All effects of camostat on the pancreas were reversible.
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Situations causing high postural stress during the transport of dustbins were determined, and the load on the spine was estimated. Electromyographical analyses revealed workload situations with high muscular activities during the transport over edges. Thus the manipulation of large dustcontainers (1100 l) is rendered difficult by kerbstones. Because smaller dustbins (110 l-240 l) are often kept in basements or backyards, stairs must frequently be climed with a heavy load. To quantify the spinal stress, a biomechanical model was developed in order to calculate the torques and forces effective at the lumbosacral joint. In the computations several parameters and transport conditions, such as kerbstone height, were varied. That entails different working postures by the dustbins men. The influence on the load on the spine was estimated. The calculated results are compared with criteria taken from the literature. Special postures were devised to keep the torques and forces as small as possible, and thereby to decrease the health risk of the skeletal system when handling heavy weights like dustbins. In the case of a container transport, only two persons should manipulate and work in well-timed co-ordination and both in special postures. Finally, all dustbins should be positioned at places guaranteeing an easy transport over flat surfaces.
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Description of various affections of the iris which may be treated with argon-laser. The problem of the laser iridectomy in the treatment of glaucoma is illustrated by a histologic study of the evolution of the lesions up to four months after coagulation of rabbit's iris.
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There is unanimous agreement on the need for primary stabilisation of non-infected and infected non-unions of long tubular bones. It is possible to draw up a general schema. With regard to the type of bone transplant usually required, we can make use of purely cortical, corticospongy and spongy bone chips. It is also possible to delimitate the appropriate fields of indication. An essential prerequisite for the proper healing of a bone graft is the stability and satisfactory vascular reaction of the transplant bed. The article describes and discusses the results of such treatment of non-infected and infected non-unions of long tubular bones, taking the above-mentioned aspects into consideration.
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