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Biomedical subjects

M Jäger

Publications and source records attributed to M Jäger.

At least 19 recordsLinked to original sources
PubMed1992

Logistical and ergonomic transportation capacity for refuse collection workers: a work physiology field study.

In a work physiology field study, the work flow and the electrocardiogram were recorded throughout whole shifts for six male refuse (garbage) collection workers who transported and emptied 1.1 m3 refuse containers. The work rate (WR), indicated by the number of 1.1 m3 containers emptied per unit of time, and the work pulse rate (WPR) were determined in the data evaluation. The work pulse rate increases with the work rate. The functional relationship can be approximated by a linear regression function (WPR = 20.9 + 35.8.WR). The work pulse rate reaches such high values that it must be assumed that the work cannot be performed continuously throughout the whole working day. Consequently, regular breaks should be provided. When determining the necessary duration of the breaks, it was assumed that an equilibrium between fatigue and recovery should be maintained during the working day. The recovery breaks should be at least long enough for the heart rate to return to the resting level. The necessary duration of the breaks was determined on the basis of the present field study and the laboratory investigations described in the literature. A minimum duration of 10 min per working hour results from the calculations. The breaks should be taken regularly at about hourly intervals. A transportation-capacity model is provided for the planning of the deployment of refuse workers. It permits calculation of the number of 1.1 m3 containers a three-man crew, comprising the refuse collection truck driver and two loaders, can empty during one shift. Both the logistical and ergonomic transportation capacities can be determined using the model. The logistical transportation capacity (TCL) indicates the number of containers which can be emptied per shift by a crew when only criteria such as the optimal utilization of the working time are considered. The ergonomic transportation capacity (TCE) is understood as the number of containers which can be emptied per shift taking into consideration the workers' strain and the recovery breaks they require. TCE amounts to between about 140 and 160 containers per shift depending on the type of city district. TCL is higher by between 20 and 30 containers per shift. In order to meet the demand of protecting workers' health, the number of containers to be emptied per shift by a three-man crew should not exceed the ergonomic transportation capacity.

Adult↗
PubMed1991

The helminth fauna of the common seal (Phoca vitulina vitulina, Linné, 1758) from the Wadden Sea in Lower Saxony. Part 1: Trematodes, cestodes and acanthocephala.

Between August 1988 and January 1989 110 common seals found dead along the coast of Lower Saxony were investigated for the occurrence of trematodes, cestodes and acanthocephala. Two fluke species, Cryptocotyle lingua Creplin, 1825 and Phagicola septentrionalis Van Den Broek, 1967, two tapeworm species Diphyllobothrium cordatum Leuckart, 1863 and Diphyllobothrium elegans Krabbe, 1865, and the acanthocephala species Corynosoma strumosum Rudolphi, 1802 were found. Phagicola septentrionalis and the cestodes were always found together with Cryptocotyle lingua. The prevalence of Phagicola septentrionalis, the diphyllobothriids and the acanthocephala increased with increasing age of the pinniped host. The worm counts of all species appeared to increase with increasing age of the host. The adult male seals were more often infested with Phagicola septentrionalis and cestodes than the female adults and the younger pinnipeds. There was no correlation between blubber thickness of the seals and parasitic infection. The prevalence of the diphyllobothriids and the intensity of the infection with acanthocephala were higher in seals found in the eastern part of the Wadden Sea.

Acanthocephala↗
PubMed1991

The helminth fauna from the common seal (Phoca vitulina vitulina, Linné, 1758) of the Wadden Sea in Lower Saxony. Part 2: Nematodes.

During the seal epidemic in 1988 and the beginning of 1989, 115 common seals found dead on the shores of the Wadden Sea of Lower Saxony were investigated for the presence of nematodes. The lungworm Otostrongylus circumlitus Railliet 1899 was found in 26.1% of the seals, the lungworm Parafilaroides gymnurus Railliet 1899 in 26.9% and the heartworm Dipetalonema spirocauda Leidy 1858 in 32.2% of the seals. In the digestive tract, two anisakid species were found, Pseudoterranova decipiens Mozgovoi 1951 in 87.8% and Contracaecum osculatum Rudolphi 1802 in 10.4% of the seals. Statistical analysis revealed a negative correlation between age of the seals and prevalence and intensity of infestation with the two lungworm species and the heartworms. Adult seals were found not to be infected with Dipetalonema spirocauda and Parafilaroides gymnurus, whereas the prevalence of the two anisakid species increased with increasing age of the seals. Pseudoterranova decipiens was found more often in autumn and winter than in summer. This parasite was more prevalent and had higher worm counts in the eastern part of the Wadden Sea than in the western part. Parafilaroides gymnurus and Dipetalonema spirocauda were found more often in seals with smaller blubber thickness than in well fed seals.

Age Factors↗
PubMed1979

[Intra-articular or extra-articular substitution of cruciate ligament--a critical study (author's transl)].

Intra- and extra-articular methods of cruciate ligament substitution are available for treating old anteromedial knee-joint instability. Twelve patients with intra-articular cruciate ligament substitution (median third of the patellar ligaments as free transplant) and 24 patients with extra-articular cruicate ligament substitution (operation according to Nciholas) were examined with particular reference to improved stability as follow-up examinations, the results being subjected to comparative evaluation. Intra-artricular cruciate ligament substitution reduces or eliminates the pre-operative instability of the joint which is due to insufficiency of the cruciate liagment, whereas the extra-articular cruciate ligament substitution produces a significantly more frequent reduction of elimination of the instability of the valgus position and of the anteromedial instability. The combination of both methods to remove anteromedial instability of the knee joint may seem a very useful solution of the problem, but it should be limited to a restricted group of patients because it involves also contain disadvantages which make it unsuitable for indiscriminate application.

Aftercare↗
PubMed1978

[An implantable femur distractor for operative leg lengthening (author's transl)].

A new femur distractor has been developed, lengthening the leg. This instrument is electronically controllable and can be implanted totally. It is possible to regulate transcutaneously by radio control the operation "forward motion", "stop" and "backward motion". After testing this instrument in sheep, the lengthening of human femur by this system can be introduced.

Bone Lengthening↗
PubMed1977

[Results of animal experiments with an implantable femur distractor for operative leg lengthening (author's transl)].

A new femur distractor for operative leg lengthening has been developed. The new instrument consists of an electronically controllable distractor set including a power unit and a two-part guide rail. The whole system can be implanted totally and gives rigid fixation throughout the period of distraction. The operations "forward motion", "stop" and "backward motion" can be regulated transcutaneously by radio control. A prototype especially developed for animal experiments has been tested successfully in sheep.

Animals↗
PubMed1977

[The unstable knee joint--aspects in basic research, diagnosis and therapy (author's transl)].

The increase of knee lesions within the last years has provoked a generally more intensive discussion about the functional anatomy, the biomechanics and the pathophysiology of the capsule and ligaments of the knee joint. Several authors have stressed the importance of the active and passive factors, stabilizing the knee joint. The injury to a single element leads to different instabilities, as proven by meticulous clinical and radiological diagnostic procedures. The progress in the treatment of fresh and old injuries of knee ligaments is connected with the names of O'Domoghue, Slocum, Larson, Hughston, Nicholas and Trillat. For a fresh completely ruptured ligament surgery is recommended. Torn menisci are reattached whenever possible. An initial graft can be necessary for ruptures of the anterior cruciate ligament. Complex injuries, which are found most frequently, have to be dealt with completely. Old injuries of capsule and ligaments may require a plastic reconstruction. For the reconstruction of the anterior cruciate ligament it has been proven useful to take distally attached tendons of the pes anserinus group as well as the free graft from the central 1/3 of the patellar ligament. Rotational instabilities have to be dealt with according to the type of instability. The techniques of Slocum and Larson and the "five in one" reconstruction by Nicholas have to be emphasized as treatment of the anteromedial rotational instabilities. McIntosh has shown a procedure which seems to be successful for anterolateral rotational instabilities. Several techniques have been compared with our own experiences and late results studied. The point is stressed that further progress has to be made for the treatment of injuries to ligaments of the knee.

Adult↗