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M Krug

Publications and source records attributed to M Krug.

105 records · Page 6Linked to original sources
PubMed1976

[Effect of psychopharmaceutic agents on cortical potentials and long-lasting post-tetanic changes in excitability released through stimulation of the dental pulp].

Short-time tetanic stimulation of the tooth pulp with square pulses affords, depending on the stimulation parameters selected, a long-lasting facilitation in the response of subsequently applied test stimuli in the sensomotor cortex of rabbits. The benzodiazepin derivatives, chlorodiazepoxide, nitrazepam (10 mg/kg i.p.) and clonazepam (1 mg/kg i.p.) caused suppression of posttetanic facilitation with partly different influences on cortical potentials following individual stimulation. Meprobamate (200 mg/kg i.p.) had no effect on the processes of posttetanic facilitation, while the amplitudes of sensomotor potentials showed a long-lasting reduction on single stimulation. Chloropromazine (2 mg/kg i.p.) showed a rapid and transient inhibition of posttetanic facilitation and reduced the amplitudes of evoked potentials following single stimulation.

Animals↗
PubMed1975

[Long-lasting changes of irritability in the somatosensory cortex of rabbits following tetanic stimulation of the tooth pulp].

Tetanic stimulation of the tooth pulp produced long lasting increases in potentials released by stimulation of the tooth pulp with single stimuli in the sensomotor cortex of rabbits. Stimulation with 200 impulses/sec for 5 sec produced changes of irritability that are demonstrable for 10-50 min depending on the intensity of stimulation. The lower rate limit for producing such changes is 25 impulses/sec. At a rate of 200 impulses/sec, a stimulation time of 25 msec was necessary to produce these changes. The postexcitatory depression occuring after single stimuli within 10-40 msec was increased by tetanic stimulation, whereas facilitation observed 5 msec after single stimuli was unaffected.

Action Potentials↗
PubMedDate not supplied

Synthesis and properties of the first all-aza analogue of a biologically active peptide.

The synthesis of the first all-aza-amino acid analogue (2) of a peptidic renin inhibitor is described. The X-ray structural analysis and molecular modelling investigations of this novel compound reveal interesting conformational features which have a significant impact on its biological activity. In addition, insight into conformational features of azapeptides in general in comparison with the corresponding purely peptidic compounds is given.

Aza Compounds↗
PubMedDate not supplied

Enhancement of glutamate release by L-fucose changes effects of glutamate receptor antagonists on long-term potentiation in the rat hippocampus.

In previous studies L-fucose has been shown to facilitate long-term memory formation and to enhance and prolong long-term potentiation (LTP). To search for possible presynaptic or postsynaptic mechanisms that are affected by L-fucose, we examined the effect of L-fucose on (1) inhibition of LTP induction via glutamate receptors by antagonists, (2) paired-pulse facilitation, and (3) presynaptic transmitter release. Coapplication of 0.2 mM L-fucose with the competitive N-methyl-D-aspartate (NMDA) receptor antagonist, D-2-amino-5-phosphonovalerate (AP5), or coapplication of 0.2 mM L-fucose in the presence of an inhibitor for class I/II metabotropic glutamate receptors, (S)-alpha-methyl-4-carboxyphenylglycine (MCPG), reversed LTP blockade in the CA1-region of hippocampal slices. In contrast, L-fucose had no effect on the LTP blockade by the noncompetitive NMDA ion-channel blocker (5R,10S)-(+)-5-Methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine hydrogen maleate (MK-801). Paired-pulse facilitation, which is a primarily presynaptic phenomenon of short-term plasticity, was decreased in the presence of 0.2 mM L-fucose. Furthermore, L-fucose enhanced the K(+)-stimulated release of [(3)H]-D-aspartate from preloaded hippocampal slices in a concentration-dependent manner. These observations demonstrate an influence of L-fucose on transmitter release that in turn can increase transmitter availability at postsynaptic glutamate receptors. This effect of L-fucose may contribute to the LTP facilitation seen in vitro and in vivo as well as to improvement in memory formation.

2-Amino-5-phosphonovalerate↗
PubMedDate not supplied

[Evaluation of the diagnosis of pigmented tumors of the skin and factors leading to a decision to excise. Dermatologists of the Postgraduate Association of Haute-Normandie].

INTRODUCTION: The necessity of excising melanomas characterized by a slight thickness at an early stage, leads dermatologists to remove pigmented lesions which do not correspond to melanomas. The aims of this study were: a) to prospectively assess the accuracy of melanoma diagnosis, b) to quantify the number of excisions performed according to the degree of melanoma suspicion, c) to determine the specific clinical sign or signs of relevant diagnostic value. PATIENTS AND METHODS: This study was conducted prospectively from January 1996 to August 1997 by dermatologists in private practice and dermatologists from a University Hospital staff. When it was decided to excise a pigmented lesion, a form was filled out choosing the most appropriate clinical diagnosis, the degree of melanoma suspicion, and clinical signs which lead to surgery. Based on histological findings as the reference, the sensitivity, specificity, accuracy of melanoma diagnosis and the kappa test that evaluates the concordance between clinical and histological diagnosis, were performed. The diagnostic value of clinical signs was assessed by variance analysis. RESULTS: Of the 353 excised lesions, 38 (10.7 p. 100) were identified as melanoma on histologic examination. The sensitivity, the specificity and diagnostic accuracy were: 79 p. 100, 94 p. 100 and 53 p. 100 respectively. The kappa test concordance between clinical and histological diagnosis was 0.66. Two hundred and two lesions (57 p. 100) were excised even though the clinical suspicion of melanoma was poorly considered. Only one of these 202 lesions was identified histologically as a true melanoma. Thirty seven (24.5 p. 100) of the 151 remaining excised lesions with an "average" or "strong" suspicion were true melanomas. The clinical signs considered, alone or associated, had a poor predictive positive value (< 38 p. 100). An analytical approach performed with a logistic model permitted the identification of two associated signs suggesting a best diagnostic value. DISCUSSION: This is the only study, to our knowledge, reported in the literature which prospectively assesses the sensitivity, specificity and concordance between clinical and histological diagnosis of melanoma. Results were considered from average to good. The originality of this study was to assess the number of pigmented lesions excised according to the degree of melanoma suspicion, suggesting the possibility of reducing the number of nevi removed when the melanoma risk was considered clinically poor. Finally, this study emphasizes the limits of clinical semiology and the need for future diagnostic methods in the assessment of melanoma.

Adult↗
PubMedDate not supplied

Radiologic evaluation of juvenile tillaux fractures of the distal tibia.

This study evaluated the accuracy of plain radiographs and computerized tomography (CT) in assessing juvenile Tillaux fractures of the distal tibia. A simulated Tillaux fracture was made in four cadaver specimens and displaced 0, 1, 2, 3, and 5 mm. Plain radiographs and CT were performed on each specimen at each amount of displacement, and the results were compared with the actual amount of displacement present. Plain radiographs and CT were accurate within 1 mm in depicting the actual fracture displacement about 50% of the time. CT was more sensitive than plain radiographs in detecting fractures with >2 mm of displacement. Fracture displacement of >2 mm is generally considered an indication for fracture reduction. Because of its sensitivity in detecting fractures displaced >2 mm, CT is the preferred imaging modality in the assessment of juvenile Tillaux fractures.

Cadaver↗