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Biomedical subjects

O Harth

Publications and source records attributed to O Harth.

9 recordsLinked to original sources
PubMed1983

Rapid determination of retinol (vitamin A) in serum by high pressure liquid chromatography (HPLC).

A simple, fast, and specific HPLC-method to estimate retinol (vitamin A) in serum is reported. In the presence of small amounts of acetonitrile retinol is extracted quantitatively with n-hexane from serum. Neither the use of an internal standard nor evaporation to concentrate the extract is necessary. The HPLC-method avoids interferences of substances like phytofluenes, carotinoids or retinyl palmitate which is present in serum to a fraction of about 2-5%. The HPLC-method was applied to healthy adults and healthy children. The method allows about 100 determinations per day and operator.

Adolescent↗
PubMed1982

[Is the angled-tube method useful for measuring sedimentation of blood corpuscles after Westergren? (author's transl)].

Results obtained with the classical Westergen method for measuring erythrocyte sedimentation rate was compared with a method in which the tubes were angled at 60 degree. Blood was obtained from 31 healthy controls and 30 hospitalised patients. Blood from the controls gave similar results with both methods. On the other hand, in patients with a raised ESR by Westergren, the two methods agreed in only 10% of cases. In most instances the angled-tube method gave values below those by Westergren, although elevated under clinical aspects. In some Instances the angled-tube method gave such low readings in clearly pathological samples that the ESR was falsely interpreted as normal. It is concluded that the angled-tube method is not valid for ESR measurement after Westergren, because it measures something different than the classical Westergren method.

Adolescent↗
PubMed1981

[Estimation of vitamin A (Retinol) and retinol-binding protein (RBP) in serum of hearing impaired children (author's transl)].

Retinol and Retinol-binding protein are estimated in the plasma of 91 children with hearing impairments of different etiology and 35 normal children of similar age. The concentrations of Retinol and Retinol-binding protein are age-dependent but in a given age class the concentrations of these substances are found to be similar in both groups. It is obvious, however that the concentrations in children with Alport-syndrome lie mainly in the upper range, while these with Pendred-syndrome have values in the lower range of the total distribution curve.

Adolescent↗
PubMedDate not supplied

Vestibular function in the space environment.

Adaptation to the weightless state and readaptation after space flight to the 1-G environment on the ground are accompanied by various transitory symptoms of vestibular instability, kinetosis, and illusory sensations. Aside from the problem of how to treat and if possible prevent such symptoms, they offer a clue to a better understanding of normal vestibular functions. Weightlessness is a powerful new "tool" of vestibular research. Graybiel reported as early as 1952 that human subjects observed the illusion that a real target and the visual afterimage seemed to raise in the visual field during centrifugation when the subjects were looking toward the axis of rotation (oculogravic illusion). In aircraft parabolic-flight weightlessness, human subjects observed that fixed real targets appeared to have moved downward while visual afterimages appeared to have moved upward (oculoagravic illusion). It can be shown by electronystagmography as well as by a method employing double afterimages that part of this illusion is caused by eye movements that are triggered by the changing input from the otolith system. Another part of the illusion is based on a change of the subjective horizontal and must be caused by convergence of vestibular and visual impulses "behind" the eyes. This part was measured independently of the first one by using a new method. Eye movements could be prevented during these experiments by optical fixation with the right eye on a target at the end of a 24-in. long tube which was rigidly attached parallel to the longitudinal axis of an aircraft. At the same time the subject tried to line up a shorter tube, which was pivoting around his left eye, with the subjective horizon.

Acceleration↗