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Biomedical subjects

F Köhler

Publications and source records attributed to F Köhler.

At least 55 records · Page 3Linked to original sources
PubMed1980

Quantitative measurement of time-dependent thallium distribution in organs of mice by field desorption mass spectrometry.

The time-dependent distribution of the toxic heavy metal TI in mouse organs was determined after feeding 80, 130, and 160 mg/kg TI. Quantitative measurements were performed by field desorption mass spectrometry with stable isotope dilution. No pretreatment of the tissue samples, other than homogenizing and centrifugation, was necessary. The precision of the data was about +/- 10%. The main results are as follows: Heart, liver, kidney, and stomach showed an organ-specific initial uptake of TI during the first 2-3 h. This was followed by a period of washout to relatively low TI levels. Brain TI uptake was comparatively low and constant during the first 12 h. In the terminal stage (24 h) all organs, including the brain, contained increased TI levels of the same order of magnitude.

Animals↗
PubMed1980

[Abnormal pacing following defibrillation - exit block after microdislocation of the electrode (author's transl)].

Two days after a 52-year-old patient with coronary heart disease (third degree-av-block and ventricular rhythm, permanent pacemaker treatment) had a pacemaker replacement, bradycardia and pacemaker exit block occurred. After defibrillation with 300 Ws pacemaker for spontaneous ventricular fibrillation, entrance block and new fibrillation were observed. Further defibrillation lead to raising the frequency of the pacemaker and to abnormal stimulation, which in turn triggered irreversibly ventricular fibrillation and the death of the patient. Autopsy showed a micro-dislocation of the electrode and the pacemaker showed a defect of the Zener diode and abnormal stimulation with 4000 Hz ith a pulse width of 240-275 ms and a pulse interval of 1010 ms. We like to point out the importance of the stimulation threshold measurement following pacemaker replacement because of early diagnosis of electrode dislocation that can lead to ventricular fibrillation. We also describe the complication of defibrillation with a pacemaker patient and give advice for prevention of its occurrence.

Bradycardia↗
PubMed1980

[Modern postmortem coronary angiographic examination methods in the service of clinical cardiology (author's transl)].

The coronary vessels of the postmortal heart can be radiologically reproduced after being filled compactly with a contrast medium or by x-ray double contrast. All vessels are primarily filled by injecting contrast medium over the aorta, even when multiple orifices, ostiumstenoses, or artificial anastomoses exist. Further, the possibility is granted to reproduce the coronary ostia. A special process permits the radiological reproduction of postmortal coronary vessels in the same projection as used by clinical cardiologists intravitally. Stereoscopic x-ray pictures are easily produced, even when using an x-ray tube in fixed position. The radiological examination of horizontal heart slices combined with histological giant sections, allows an exact determination of the supplying areas of singular coronary vessels and their branches, as well as providing information about the relationship between coronary arterial and myocardial pathology. The double contrast x-ray method offers the advantage of a faultless reproduction of the coronary ostia and an estimation of the singular vessels, even with multiple overshadowing. In addition conclusions can be drawn from the changes of diameters of the coronary vessels under defined pressure as to the mechanical wall characteristics post-mortem. By means of these extended methods the postmortal radiological examination of coronary vessels can play an important role in the solution of scientific problems of clinical cardiology today.

Cardiology↗
PubMed1979

[Teratological aspects of CaF2 medication].

CaF2 was studied in animal experiments to determine its effect over a period of several generations. The negative effects of AcF2 on embryogenesis increase as the dosage is increased. The effects however are slight compared with other fluorides.

Abnormalities, Drug-Induced↗
PubMed1978

[A new method of comparing intravital and postmortal coronary angiography (author's transl)].

A cardanically suspended plexiglass cylinder, filled with water and containing a specific supporter, enables postmortal hearts to be x-rayed in every possible projection. After filling the coronary vessel system with x-ray contrast medium, intravital angiograms can be repeated postmortally with equitable projection. The diastolic and systolic change of ventricle size in intravital hearts as well as postmortal rigor mortis or relaxation, result in only insignificant differences between postmortem and intravital x-rays of the coronary vessels taken from the same projection. Combined with histological studies, such examinations promise further knowledge about the development of degenerative changes of the coronary vessels. The described apparatus is also suitable for comparative intravital and postmortal x-ray examinations of other organs. With its aid, stereoscopic x-ray pictures can also easily be made.

Angiocardiography↗
PubMed1978

[Comparative study of coronary vessel diameters in intravital and postmortal angiograms (author's transl)].

In a total of 21 mongrel dogs a comparison between intravital and postmortal coronary arteriograms was made so as to establish the difference in vessel diameter. Fresh postmortal hearts injected in situ showed an average increase in coronary vessel diameter of approx. 6 per cent. Examinations of 24 hour postmortal hearts which were removed from the animals showed a vessel diameter increase of barely 20 per cent in the mean. These 20 per cent correspond fairly well with literature information about the maximal widening of coronary vessels with nitroglycerin. Nerves which are still functioning, and humoral substances which may influence the still living muscle in vessel walls are supposed to be the reason for the smaller increase in fresh postmortal in situ illustrated coronary arteries. It must be stressed, that the measured differences between intravital and postmortal coronary artery diameters can only be representative of wall sections free of arterioslcerosis.

Animals↗
PubMed1977

[Extraction of tricuspid valve tissue and myocardium as a complication of transvenous cardiac pacing (author's transl)].

In a patient with transvenous cardiac pacemaker a piece of tissue, 5,5 cm in length, was removed from the wall of the right heart during the extraction of a "shouldered" electrode (Biotronik IE 85-K-O). Histologically it consisted of fibrous tissue as usually found around transvenous electrodes, tricuspid valve tissue, chordae tendineae, and myocardium. Detrimental consequences to the patient following this complication were not observed. Some problems caused by trapped endocardial electrodes and adequate therapeutic possibilities are discussed.

Electrodes, Implanted↗
PubMed1977

[Teratogenic effect of N-phthaloyl-L-aspartic acid on the mouse (author's transl)].

The optical isomers of N-phthaloyl-aspartic acid, structurally related to thalidomide, were administered i.p. to pregnant mice on day 9 of gestation; the injected solutions contained Tween 20 as solubilizer. N-Phthaloyl-L-aspartic acid exerts an embryotoxic and teratogenic effect as is evident by the high incidence of resorption and malformations. On the other hand the D-isomer is devoid of any embryotoxic and teratogenic activity under the same conditions of experiment.

Animals↗
PubMed1977

[Benign cystic teratoma (dermoid cyst) of the ovary perforated into the urinary bladder].

In a 25-year-old female patient with right-sided adnex tumour and inveterate infection on the urinary tract a benign cystic teratoma (dermoid cyst) perforated into the lumen of the urinary bladder could diagnosed cystoscopically. As therapeutic method of choice the tumour with the adjacent part of the wall of the urinary bladder was operatively removed. The histological investigation confirmed the right ovary as starting point of the tumour. Pathogenetic and etiologic points of view of the perforation of dermoid cysts of the small pelvis into adjacent hollow organs are discussed in short. When a perforation into the lumen of the urinary bladder is present, among others the clinical symptoms of the flux of hair and fatty paste with the urine belonging to this give good diagnostic references.

Adult↗
PubMed1977

[About some rare complications caused by transvenous pacemaker electrodes. Morphological and clinical findings (author's transl)].

Early and late dislocation of electrodes incl. perforation of myocardium and infections of pacemaker systems are the most frequent complications during endocardial pacing. Next functional disorders caused by a risen threshold for stimulation and sensing problems as well as pure technical defects have to be mentioned. The following rare complications were observed in three autopsies: 1. Electrode located in the vena cordis media. 2. Bipolar pacemaker electrode in unstable position near the atrioventricular boundary. 3. Infected transvenous pacemaker electrode migrated into the right vena iliaca externa. Letal thromboemboli sm of the pulmonary arteries. 4. Electrode fragment causing chronic cervical fistula. Consecutive death of the patient by bacterial endocarditis of the mitral valves. Some morphological and clinical aspects of these complications are discussed, the literature is reviewed. Special sight is kept on "trapped" electrodes and coincident infection. It is considered how to avoid those accidents.

Aged↗
PubMed1977

[Site and shape of the most severe stenoses in coronary arteries and their relationship to the risk factors. Postmortem findings (author's transl)].

Out of a great number of hearts investigated post-mortem by coronary arteriography and quantitative histology, 437 coronary arteries of 202 hearts had severe stenoses with a lumen reduction to less than 50 per cent. Mainly these most severe obstructions lay between 2 and 5 cm behind the aortic ostium. In the right coronary artery the frequency curve showed a smaller peak, a smaller decrease, and an inconsiderable second peak in the periphery. Perhaps the slow calibre reduction of the right coronary artery is significant for these findings. The narrowed lumen mostly lay a little eccentric and had an oval shape. A slit-like shape was a rare finding. Only in 20 per cent of the severe stenoses a normal intima was preserved in parts of the circumference of the coronary artery. Among 113 patients the following risk factors were known: hypertony, diabetes mellitus, cigarette smoking and hypercholesterinemia. Significant differences in the localisation of the most severe stenoses were not recognizable under the influence of these risk factors.

Aged↗
PubMed1977

[Experiences with transvenously implanted pacemaker electrodes with special remarks on the treatment of leads out of function (author's transl)].

From 1965 to 1976, implantations of 502 pacemaker electrodes were performed. In 59 patients the first lead had to be changed. In December 1976, 355 patients were under our control. At this time, 11.7 percent were no longer paced via their first lead. Dislocations of the lead, increased threshold, insulation defect, skin perforation of the lead, myocardial perforation, adaptor defects, fracture, infection, and loops of the electrode were the reasons. In cases of exit block alone, you should try to take a high output pacemaker. In cases of entrance block, a pacemaker with increased input-impedance will do its work. If those two kinds of treatment will fail, you may speak about a lead out of function. Considering extraction of the electrode, except in cases of infection, you should exercise restraint, for severe complications may result. An electrode out of function has to be protected against disappearing in a safe way. A synopsis of electrode complications including cause, therapy, and prevention is given.

Electrodes, Implanted↗
PubMed1976

Teratogenicity and embryotoxicity of some maleinimides.

Maleinimide, the teratogenic structural "central part" of the thalidomide molecule, and 5 of its dichloro- and dibromo-derivatives have been investigated teratologically by tests on SWS mice. According to both the electrophilic properties and the spatial requirements of the substituents, the effects were found to be up to 100 times stronger than those of thalidomide, and up to 10 times stronger than those of phthalimide respectively. The results are referred to the distinct electron-acceptor behavior of the maleinimide compounds, which--due to their flat molecular structures--are able to intercalate into the DNA double helix forming EDA complexes with nucleic acid bases as electron-donor molecules. The results can be interpreted as another confirmation of Jönsson's intercalation hypothesis of the thalidomide action.

Abnormalities, Drug-Induced↗