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Biomedical subjects

H Vogel

Publications and source records attributed to H Vogel.

At least 253 records · Page 14Linked to original sources
PubMed1987

[Foreign body injuries in nuclear magnetic resonance tomography].

The hazard involved in MR tomography if there are foreign parts in the body made of metal, is assessed. There are certain hazard-influencing factors. As far as the foreign body is concerned, these are: ability to become magnetized, size, length, elasticity, sharp edges or ends, and sharp surfaces. In the human body itself, risk factors are determined by the position of the foreign body in or near sensitive organs such as cerebrum, nerves, vessels, lungs, eyes, ears and the heart; other factors are the fixation to bones or lack of fixation in hollow organs. One should assume when assessing the risk that the foreign body consists of iron that is capable of complete magnetisation. In that case the attacking forces will not exceed the 25 to 36 fold value of the foreign body's own weight. It is thus possible to predict with some measure of probability whether the position of the foreign body will shift during MR examination and whether the examination can result in injury.

Bone and Bones↗
PubMed1987

[Sonography of the knee joint].

The results of the ultrasound investigation of 300 patients are described. The procedure and the normal anatomy are demonstrated. Pathological findings are effusion, joint ganglion, chondromalacia, loose bodies in the joint, Baker-cysts and ligamentous lesions. It is probable that future improvement of the equipment will enlarge the diagnostic possibilities.

Humans↗
PubMed1987

[Roentgen diagnosis following knee surgery].

After ventralization of the tibial tuberosity (Bandi-operation) the elevation can be shown. Chip and cortical fractures radiologically are demonstrated. After medialization of the patella ligament (Roux-Hauser operation) the site of excision is seen as a hyperlucent area and the site of apposition as a hyperdense area. After implantation of a sledge prosthesis risk factors indicating future complications can be identified by early postoperative radiography.

Aged↗
PubMed1987

[Complications of arteriography--details at the time of the occurrence of side effects].

Own observations and the review of the literature show that complications of arteriography may appear after some hours or some days. The causal context is given in general for complications that may be due to the puncture. This is valid, too, for renal insufficiency induced by contrast substance. Neurological symptoms appearing hours or days after cerebral angiography are more difficult to evaluate. Different influences may contribute. The information of the patient before arteriography may in some cases include complications of possible follow-up treatment.

Angiography↗
PubMed1986

Models for the structure of outer-membrane proteins of Escherichia coli derived from raman spectroscopy and prediction methods.

The secondary structure of porin, maltoporin and OmpA protein reconstituted in lipid membranes is determined by Raman spectroscopy. The three proteins have similar structures consisting of 50 to 60% beta-strand, about 20% beta-turn, and less than 15% alpha-helix. Employing a method for structural prediction that accounts for amphipathic beta-strands, folding models are developed for porin and for the segment of OmpA protein incorporated into the membrane. In the model, the OmpA fragment consists of eight amphipathic membrane-spanning beta-strands that form a beta-barrel. Similarly, porin is folded into ten amphipathic membrane-spanning beta-strands that are located at the surface of the trimer towards the lipids and eight predominantly hydrophilic strands in the interior.

Amino Acid Sequence↗
PubMed1986

European vestibular experiments on the Spacelab-1 mission: 2. Experimental equipment and methods.

A series of vestibular experiments were performed in conjunction with the first Spacelab mission, consisting of sets of pre-, in- and postflight tests. A multipurpose experimental apparatus used for the diverse flight and ground tests is presented. Additional apparatus together with the multi-purpose package were used in the baseline data collection facility at the landing site at NASA Dryden Flight Research Facility for the ground tests. The tests involved optokinetic, caloric and mechanical (whole-body or head-alone) stimulation. The latter included linear acceleration in the subject's x, y and z axes, static roll and yaw about an earth-vertical axis. Physiological parameters such as electro-oculogram (EOG), blood-volume-pulse (BVP), respiration, as well as the stimulus variables such as acceleration and caloric temperature were transmitted to the ground and recorded there. The flight and ground testing schedules are outlined. Problems arising from this complex venture are discussed, and some suggestions are made for future improvement.

Acceleration↗
PubMed1986

European vestibular experiments on the Spacelab-1 mission: 4. Thresholds of perception of whole-body linear oscillation.

Thresholds for the detection of linear oscillatory motion at 0.3 Hz in the X, Y and Z body axes were determined during the flight of Spacelab-1 and on the ground pre- and post-flight, using the method of limits with a single staircase procedure. Pre-flight, Z axis thresholds (mean 0.077 ms-2) were significantly higher than X and Y thresholds (mean 0.029 ms-2). Measures obtained on three crew members in-flight exhibited thresholds greater, by a factor of 1.5-4.3, than those obtained pre-flight. Post-flight, two crew members had significantly elevated X and Y axis thresholds whereas the other two crew members had lowered thresholds in X, Y and Z axes. In general, thresholds had returned to pre-flight levels by the second post-flight day. A possible explanation for these somewhat disparate responses is presented.

Acceleration↗
PubMed1986

European vestibular experiments on the Spacelab-1 mission: 7. Ocular counterrolling measurements pre- and post-flight.

The static ocular counterrolling (OCR) of the four scientific crew members in the first Spacelab mission was measured during baseline-data-collection before and after the flight of SL-1. It was presumed that the modification of otolithic responses during spaceflight will be reflected in specific changes of the OCR-gain on the first days after recovery. The magnitude of OCR was determined analysing colour-transparencies of subjects right eyes that were produced in different positions of lateral body tilt. In general, one subject did not show any changes at all; three subjects exhibited a significant decrease of OCR-gain after exposure to weightlessness, whereby differences could be found between the responses for small and large angles of lateral body tilt. Moreover, asymmetrical effects of OCR-gain were found between body tilt to the left and tilt to the right side. Two subjects already demonstrated such an asymmetry before the flight with the higher gain on left-tilt (or right eye up), and three subjects exhibited left-right asymmetries after the spaceflight with the higher gain tilting to the right (or right eye down). A possible correlation between these vestibular asymmetries and space-sickness susceptibility is discussed.

Adaptation, Physiological↗
PubMed1986

Desquamative interstitial pneumonitis and alveolar lipoproteinosis: diagnostic difficulties and therapy problems with an infant.

A desquamative, interstitial pneumonitis was diagnosed histologically in a 9-month-old boy who first became ill at the age of 5 weeks. The desquamative interstitial pneumonitis was associated with an acquired cytomegalovirus (CMV) infection. Despite treatment with corticoids, acyclovir and artificial ventilation, the patient died of pulmonary insufficiency at the age of 15 months. The autopsy revealed an alveolar lipoproteinosis.

Cytomegalovirus Infections↗
PubMed1986

Subjective vertical before and after space flight.

Three scientist astronauts on the D1 spacelab mission participated in a series of orientation experiments before and after exposure to orbital weightlessness. Each subject was tilted about a roll axis at 15 deg intervals up to +/- 90 deg. At each angle the subject set a luminous line to what he perceived to be the vertical. The results of these tests are presented.

Adaptation, Physiological↗
PubMed1986

The structure of melittin in membranes.

The conformation of the polypeptide melittin in lipid membranes as determined by Raman spectroscopy is a bent alpha-helix formed by the mainly hydrophobic residues 1-21, and a nonhelical COOH-terminal segment of the hydrophilic residues 22-26. Fluorescence quenching experiments on residue Trp19 reveal that all COOH-termini are located on that side of a vesicular membrane to which melittin was added. By means of fluorescence energy transfer between unmodified and modified Trp19 residues, melittin is shown to aggregate in membranes predominantly in the form of tetramers. These and previous results on the location and orientation of melittin permit the development of a model for the structure of melittin tetramers in membranes. The hydrophilic sides of four bilayer-spanning helices face each other to form a hydrophilic pore through the membrane.

Bee Venoms↗