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Biomedical subjects

J Kramer

Publications and source records attributed to J Kramer.

At least 253 records · Page 14Linked to original sources
PubMed1979

[Thermographically visualized cutaneous reactions after irradiation with fast electrons (author's transl)].

A comparison was made between thermographically visualized cutaneous reactions of two groups of patients after a therapy with fast electrons. One group underwent one-series irradiation, the other group received two series with an interval of 21 days. The cutaneous reaction after the interval only appeared following considerably higher doses than with one-series therapy. This difference indicates the recuperative capability of normal tissue after the exposition to subtolerance effects. The data were evaluated using a function derived from the Ellis-formula. A "biological dosimeter" can be developed based on thermic reactions of subcutaneous connective tissue.

Electrons↗
PubMed1979

Periodic respiration. The capnographic interpretation.

Different type of periodic respiration are difficult to distinguish clinically although their identification may influence the diagnosis, prognosis and treatment. Often other forms of abnormal respiration are mistaken for periodic. Four capnograms are shown illustrating (1) true Cheyne-Stokes respiration, (2) irregular "pseudo-periodic" respiration a) after fentanyl, and b) in the presence of a brain tumour and (3) regular respiration interspersed with deep sighs which was diagnosed clinically as Cheyne-Stokes respiration. A plea is made for the routine use of capnography in order to provide a visual record of respiration.

Carbon Dioxide↗
PubMed1978

Paradoxial response to dopaminergic agents in parkinsonism.

A patient with the classical stigmata of parkinsonism was treated on three separate occasions with levodopa, a combination of levodopa and carbidopa, and lergotrile mesylate, a direct-acting dopamine-receptor agonist. All three treatment regimens resulted in dose-related increases in parkinsonian features. To our knowledge, this response has not been previously described. Lergotrile did not alter CSF homovanillic acid concentration. It is suggested that this rare paradoxical motor response to dopaminergic agents may be associated with dysfunction of the postsynaptic dopamine receptor site.

Acetonitriles↗
PubMed1978

Physostigmine for cardiac and neurologic manifestations of phenothiazine poisoning.

Psychotropic drugs such as the phenothiazine neuroleptics and tricyclic antidepressants are known to cause electrocardiographic abnormalities as well as a central anticholinergic syndrome. Physostigmine is known to reverse the central muscarinic anticholinergic manifestations by inhibition of the enzyme cholinesterase. An unusual case of trifluoperazine overdose, in which the patient presented with cardiac arrhythmias and a central anticholinergic syndrome, is presented. Treatment with physostigmine reversed the central anticholinergic syndrome as well as the electrocardiographic abnormalities. Effects of phenothiazines on altering cardiac status are also discussed.

Antipsychotic Agents↗
PubMed1978

Getting started with a scanning transmission electron microscope coupled to a small computer.

A scanning transmission electron microscope (STEM) equipped with a laser-heated gun was coupled to a small computer. Several alterations to the commercially obtained parts of this system are described. On-line operation procedures were developed aiming to reduce the amount of radiation of the specimen area of interest. The resulting system is capable of recording information at the 1.0 to 1.5 nm resolution level by taking advantage of the efficiency of a STEM in recording the information and in controlling the irradiation conditions. These features are important in the study of biological material.

Computers↗
PubMed1978

Prolactin suppression by (-) delta-9-tetrahydrocannabinol (THC): involvement of serotonergic and dopaminergic pathways.

(-) delta-9-Tetrahydrocannabinol (THC) was previously shown to suppress serum PRL levels (SPL) in rats. In the present study, various pathways by which THC suppresses PRL secretion were investigated. THC abolished the elevated SPL induced by either 5-hydroxytryptophan or melatonin. The SPL suppression after THC treatment was abolished upon treatment with cyproheptadine. These results suggest on involvement of a serotonergic pathway in the suppressive effect of THC on PRL secretion. Elevated SPL induced by a low dose of the dopaminergic blocker pimozide was suppressed after treatment with THC. However, elevated SPL, induced by a high dose of pimozide or by any dose of perphenazine (a less specific dopaminergic blocker), were not reduced by combined treatment of either of these drugs with THC. It seems that THC also enhances the dopaminergic activity in the pathway that controls PRL secretion. In addition, the pimozide-induced SPL elevation dropped upon combined treatment of cyproheptadine and pimozide. As cyproheptadine alone, and in the dose used, did not affect SPL, it is proposed that the serotonergic and dopaminergic pathways that control PRL secretion do not necessarily act independently of one another.

Animals↗
PubMed1976

Comparison of Frank's and McFee's lead systems using multivariate statistics.

Two widely used orthogonal corrected 3-lead system - the Frank and the McFee systems - were studied in order to evaluate whether a significant difference in diagnostic performance could be observed; in the case of a positive answer, we would be able to advocate one system instead of the other. No such overall difference was noticed. Although +/- 17% discrepancies were found on the individual classification level (a patient correctly classified with system A and missed with system B and conversely), the practical implication is negligible since each system is responsible for +/- half of these discrepancies. Multivariate analysis, as already largely proved by Pipberger's group, drastically ameliorates the diagnostic results. Special caution has been given to the number of selected discriminators in order to enhance repeatability of the results; the reproducibility, using the approach developed by Cornfield, was found excellent. Some particular features as to the choice and location of the best discriminators were found somewhat puzzling by the autors but no deterministic explanation could be offered: the selection of the variables, indeed, rested on statistical bases and not on the (sometimes fragmentary) knowledge of what is going on in the heart and how these events relate to surface waveform patterns.

Adult↗
PubMed1975

The ischemic leg: a clue to dissecting aneurysm.

The acute ischemic leg may be an important clue to the diagnosis of a dissecting aneurysm. Seventeen of 65 patients with dissecting aneurysms presented with this picture. The ischemic leg was often the dominant feature and obscured the correct diagnosis. The possibility of aortic dissection should be considered in any patient with an acutely ischemic leg, especially if there is any accompanying chest, neck, or back discomfort. The presence of an ischemic limb is not necessarily an indication for surgical repair of the dissection itself. Of seven patients treated medically, five survived with limbs intact, and in all five the pulses returned within one month.

Adult↗