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Biomedical subjects

J Koch

Publications and source records attributed to J Koch.

At least 217 records · Page 12Linked to original sources
PubMed1987

[New aspects of causal therapy of hearing and speech development disorders caused by cleft palate].

Seromucous effusions were found in the tympanum in 91% of 208 cases of cleft palate. The incidence of recurrent mucosal effusions after paracentesis alone, in addition to drainage of the middle ear and poor speech results after veloplasty alone (according to Schweckendieck), led to the realization that hearing and speech disturbances in patients with cleft palates must be treated with a combination of morphologically correct veloplasty and tympanic drainage. Taking into consideration the fact that the auditory canal reaches maturation at the end of the first year of life, this procedure should be performed before the patient is 12 months old.

Child↗
PubMed1986

Kinetic distribution model for chemicals based on results from a standard environmental system.

In order to reduce potential hazards to the environment resulting from production and use of chemicals, some governments have enacted laws and corresponding regulations. Thus, for instance, the German "law on hazardous substances," and the regulation regarding a.o. submission of test data on physiochemical properties of new substances, have been ratified by the Federal Republic of Germany legislation in 1980 and 1981, respectively. This implies that before production, marketing, and use of a new chemical, its potential hazard to human beings and the environment has to be checked. Therefore it is necessary to have available accurate information about the probable fate of this new chemical in the environment, i.e., its distribution among the different environmental compartments. To this end, the submission of basic physiochemical data of a new chemical, such as boiling point, vapor pressure, water solubility, fat solubility, and partition coefficient in the system n-octanol/water, is mandatory for its registration. These data are meant to be used by the official evaluating department as a basis for describing the distribution behavior of the substance in the environment. However, there is no generally accepted procedure yet which would allow the reliable prediction. Such a calculation procedure should comprise all factors decisive for distribution and degradation of chemicals in the environment, according to their significance. We have taken a first step in this direction by carrying out the following experiments, with the aim of developing such a distribution model as well as identifying the physicochemical properties of chemicals required for the prediction of distribution patterns. The distribution patterns of 12 selected substances, having significant differences with respect to their physiochemical properties, were determined via radiotracer technique, in a defined, standardized, terrestrial ecosystem. The results of the experiments were compared with one another as well as with values calculated by use of mathematical models from the literature. These comparisons show that there are certain correlations between the distribution patterns obtained by experiments and those calculated by the stationary distribution models. However, these also indicate that some of the experimental findings cannot be explained within the framework of stationary distribution models. Kinetic models represent a more universal approach toward predicting the distribution of chemicals in an ecological system. Various prototypes are described in the literature but we could not use them due to their mathematical shortcomings.(ABSTRACT TRUNCATED AT 400 WORDS)

Chemical Phenomena↗
PubMed1986

Performance of normal and neurological mutant mice on radial arm maze and active avoidance tasks.

The objectives of the present study are to assess the import of gene-imposed structural alterations on behavioral performance and obtain performance data preliminary to studies of experimental mouse chimera behavior. Reeler, staggerer, and weaver neurological mutant, and control B6C3 and ichthyosis mice were tested on radial arm maze and active avoidance tasks. Weaver mice had incapacitating seizures while performing the radial arm maze task and were, therefore, removed from further testing. Staggerer mice displayed a significant deficit on both tasks compared to control mice. Homozygous reeler mice (rl/rl) also had a significant deficit on the active avoidance task compared to +/rl control mice but not significantly poorer than ichthyosis mice. However, their performance on the radial arm maze task, while initially poor, improved so that they performed the task similar to wild-type controls. Three of the reeler mice reached criterion for solving the radial arm maze task. None of the staggerer mice reached criterion. These data are discussed in terms of the value of using neurologically mutant mice in dissecting structural-functional relationships. It is suggested that the behavior of these mutants might point toward specific components of cerebellar involvement in behavioral acts.

Animals↗
PubMed1986

RADFOOD--a dynamic model for radioactivity transfer through the human food chain.

Radioactive fallout presents a short-term risk due to its direct deposition on agricultural crops, as well as a long-term risk resulting from its deposition on soil and subsequent uptake by crops. A dynamic model, RADFOOD, was developed, based on different existing models. It simulates transport of fallout radionuclides through agricultural food chains to man and evaluates the radiation doses resulting from consumption of contaminated food. Transport was modeled through compartments representing various environmental elements of food products. Internal radiation doses (whole-body weighted doses) following ingestion of contaminated foodstuffs were then estimated. Specific types of crops, soils and diet of man and livestock were considered. A sample calculation was performed in which individual and collective radiation doses, as well as associated health effects, resulting from fallout contamination were evaluated. They were estimated for food consumption beginning at various times after the fallout deposition and for different consumption durations. A sensitivity analysis, performed for the main model parameters, showed that the radiation dose is sensitive, for the short-term period, to changes in initial deposition levels and in the parameters characterizing initial fallout interception and resuspension.

Food Contamination, Radioactive↗
PubMed1985

Downbeat nystagmus as a side effect of lithium carbonate: case report.

In this case study, lithium carbonate, used to control bipolar disorders, is postulated to be the cause of downbeat nystagmus; the degree of nystagmus could be correlated with the dosage and serum level of the drug. All tests for anatomic lesion were negative, including metrizamide cisternography.

Basal Ganglia Diseases↗
PubMed1985

[Experiences with the combination of communication training and dynamic group psychotherapy].

Three psychotherapy groups consisting of altogether 37 patients took part in communication training after L. Schäbisch and M. Sieme in preparation for group-centred dynamic psychotherapy. The results of pretherapy and post-therapy surveys with the MMPI were tested for quantitative changes using Posthoff and H. F. Böttcher's gnoseologically based test. The findings suggest that this combination of methods has a high standard of efficiency, which is finally discussed.

Behavior Therapy↗