Biomedical subjects
Publications and source records attributed to H Koch.
The transplantation of seven human small cell lung cancers (SCLC) into athymic nude mice resulted in the development of three tumor lines that are suitable for study of biology and for tests of new drugs and combinations. They were characterized and the response to known drugs was determined. An identical tumor response was observed in the nude mouse system and in the patient in all four comparisons available.
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The capacity of bacterial plasmid vector pAT 153 for harbouring and for amplifying in a stable way a very large insert of foreign genetic material was screened. The DNA of a tree shrew herpesvirus (strain 2) with a molecular weight of about 130 megadalton (200 kilobasepairs) consisting of a long unique DNA sequence without direct and inverted repeats (greater than 40 basepairs), was used for molecular cloning. A successful insertion and stable amplification of a DNA fragment with 49 megadalton (74 kilobasepairs) cloned in Eco RI site of pAT 153 was performed, which resulted in the construction of recombinant DNA plasmid pTH2-E-C1. The stability of the recombinant plasmid pTH2-E-C1 with a super insert of 74 kilobasepairs (49 MD) indicates that the bacterial plasmid vector pAT 153 has really a high capacity for harbouring foreign genetic material.
The present investigation provides evidence that the second messenger cyclic adenosine monophosphate (cAMP) shows a different reaction before and after treatment of asthmatic attack. 18 patients suffering from an asthmatic attack admitted to hospital as internal emergency cases were given intravenously 0.24 g theophylline-ethylenediamine (Euphyllin) and 10 mg benzoctamine. Blood was taken and cAMP-concentrations were tested during status asthmaticus, i.e. before theophylline was injected, and after symptoms had decreased. After injection of theophylline a relation could be shown between the clinical effect and a significant biochemical correlate. The cAMP-concentrations increased from 15.5 to 20.2 pmol/ml. The results are significant on the 1% level. It should be discussed whether there is a malfunction or a lack of receptors in asthmatic disease. The cAMP-concentrations found during status asthmaticus are low compared to those found during paroxysmal tachycardia (40 pmol/ml) and are slightly higher than those found in healthy persons. There was no depressant effect on respiration by benzoctamine; in spite of that good sedative component could be seen.
The sensitivity against optochin of 491 strains of Streptococcus pneumoniae respectively alpha-haemolytic Streptococci was tested in optochin-plate-method and in the diffusion-test. Discs impregnated and used in wet condition and dry discs prepared in one of the participating laboratories were equal in their efficiency. The differentiation of Streptococcus pneumoniae and alpha-haemolytic Streptococci is possible by the disc-diffusion method using the following limit of inhibition zone. Streptococcus pneumoniae diameter of inhibition zone greater than 15 mm alpha-haemolytic Streptococci diameter of inhibition zone 0-15 mm The industrial production of optochin-discs can be recommended.
Hemangiomas of the liver are a common fortuitous finding during ultrasonographic studies of the liver. Although they often present a characteristic ultrasonographic pattern, it is not always possible to exclude malignant disease. Diagnostic difficulties may arise when known malignant disease is present. Computed tomography and angiography do not exclude misinterpretations. In nine patients, six of whom had known malignant disease, liver tumors were detected at ultrasonography. Using a new type of fine needle and ultrasonographic control, biopsy provided the histological diagnosis of hemangioma in all cases. Complications were not observed.
A new double-channelled catheter with one main lumen and one accessory small lumen is described. The different ranges of application and the advantages are discussed. Flow rates through the two channels are measured and compared with the well-known "Cavafix"-system. Reactions of incompatibility and possible changes in efficacy of drugs and infusions can be provided with this kind of central venous catheter.
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Accurate flow cytometric determination of nuclear DNA fluorescence has been attempted with human amniocentesis materials employing a detergent nuclear isolation protocol and 4,6-diamidino-2-phenylindole (DAPI) staining. Assay of native fluids yielded inadequate fluorescence histograms, whereas analysis of cultured amniocytes yielded unimodal histograms in 80 of 83 samples. Three fluids displayed unexpected bimodality, which may have resulted from the interaction between detergent and chromatin in rare cell types. Using a standardized protocol for preparation, staining, and assay, including brief periods of cocultivation of a human triploid reference standard, the percent experimental error in the flow cytometric DNA content estimate was as low as 0.2% in repeated assays of a single sample, and 0.4% in assays of a given genotype at different occasions. In two series of blindly assayed specimens, the percent standard error of the DNA content estimate ranged from 0.6 to 1.0%.
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In a running clinical prospective study on the incidence of adverse reactions to colloidal polysaccharides (randomised, single blind, n = 300) a bronchospasm followed by cardiac arrest occurred during dextran infusion although the necessary hapten blockage with monovalent dextran-1 had been effected. Resuscitation was successful. Directly after this, surgery was carried out as planned under general anaesthesia. The 69-year-old patient was discharged without noticeable sequelae. For the first time in the literature on dextran the studied sample allows a generalisation: The event occurred with an incidence of about 0.9% (of 116 patients who had received dextran infusion). This incidence corresponds to a confidence interval ranging from 0.02 to 4.96%. If the study would be continued as planned, the upper limit of this interval signals the probability of another case of severe intolerance. The diagnosis "dextran adverse reaction" can be made in this case by clinical symptoms. Since no previous or concomitant medication had been administered as provided in the protocol to confirm the diagnosis as an adverse reaction to dextran by determination of the titer of dextran antibodies prior to infusion is not required and it may be concluded that dextran was the causative agent.
From 1976 to 1982 in 279 patients amongst 3719 laparoscopies focal fatty liver infiltrates were found at the right and/or left liver edge next to the insertion point of the round ligament. These so-called "yellow spots" mainly could be recognized in case of normal liver tissue and in cases suffering from chronic hepatitis insofar as a cirrhotic transformation or a significant fibrosis had not taken place. The localization and the shape of these focal lesions indicate, that an abnormality in the portal blood supply of the corresponding area may play an etiologic role for the development of the fatty infiltration.
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A new double-channelled catheter with one main canal lumen and an accessory small lumen and its different ranges of applications are discussed. Reactions of incompatibility and possible changes in efficacy between drugs and infusions can be provided with this new form of a central-vein-catheter.
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