Sichere Lagekontrolle von Magensonden: ein oft unterschätztes Thema zur Vermeidung potenziell schwerwiegender Komplikationen

Die Anaesthesiologie - Die Anlage einer Magensonde im OP oder auf einer Intensivstation (ITS) stellt eine alltäglich durchgeführte Prozedur dar. Obwohl die Sonde häufig durch...     

Optical non-invasive technique for vessel imaging: I. Experimental results

This paper investigates some prerequisites for vessel imaging based on diffuse reflectance measurements in order to develop an optical non-invasive method for the imaging and monitoring of vessels. The method utilizes near-infrared (NIR) radiation (890 nm) from a light emitting diode. The light is guided into the tissue via an optical fibre (diameter 1.0 mm). The backscattered light is collected by an optical fibre of the same type and detected by an optical power meter. The fibres are moved over the skin in two directions with the aid of two motors operated by a microcomputer. Spatially resolved reflectance at the skin surface could be presented as a vessel-map in a colour-coded form on a computer screen. Experimental results indicate that the vessel imaging facility depends upon source-detector separation, relative position and vessel depth, and does not depend essentially on the radiant power from the light source. It is shown that, by a proper choice of probe parameters, one can improve the vessel identification ability. After vessel imaging the technique can potentially be used to monitor several physiological parameters on a selected vascular bed or to distinguish between injured and healthy tissue by monitoring local blood flow, oxygen saturation and the recirculation, pre- and post-operatively.     

Structural and steric requirements for β-phenethylamines as agonists of the noradrenergic cyclic AMP generating system in the rat limbic forebrain

Summary The present studies were undertaken to assess the structural and steric requirements for -phenethylamines as agonists of the noradrenergic cyclic AMP generating system in slices of the rat limbic forebrain. Significant agonist activity of -phenethylamines requires a -3,4-dihydroxyphenethylamine with a -hydroxyl group in the R configuration. Thus, dopamine did not stimulate the system at concentrations up to 10^–3 M. Moreover, -hydroxyphenethylamines without a 3,4-catechol group (octopamine, phenylephrine, p-hydroxynorephedrine, metaraminol and methoxamine)-though exerting -agonist activity in peripheral tissues-lack agonist activity in this particular cyclic AMP generating system. The effects of (R)-norepinephrine and (R)-isoproterenol at maximal concentrations were not additive. The results lend further support to the view that the cyclic AMP generating system in slices of the limbic forebrain is part of a norepinephrine receptor coupled adenylate cyclase system with a subpopulation of receptors that are in nature.     

Modification of the noradrenergic cyclic AMP generating system in the rat limbic forebrain by amphetamine: Role of its hydroxylated metabolites

Summary The cyclic AMP responses to norepinephrine (NE) in slices of the rat limbic forebrain after the administration of (S)-amphetamine and the role of its para- and -hydroxylated metabolites were investigated. The chronic but not acute administration of (S)-amphetamine to rats causes a significant reduction in the sensitivity of the cyclic AMP generating system to NE without changing the basal level of the nucleotide. This change in the sensitivity of the system is not associated with a change in the EC₅₀ value for NE but reflects mainly a decrease in the maximal response. After withdrawal of the drug, the cyclic AMP response to NE returned to control values within 4 days. In vitro, (S)-p-hydroxyamphetamine (POH) and all stereoisomers of p-hydroxynorephedrine (PHN) except (S,R)-PHN enhanced the cyclic AMP response to low concentrations of NE. Since (S,R)-PHN [like the other stereoisomers of PHN and (S)-POH] inhibited in a dose-dependent manner the high affinity uptake of ³H-NE into crude synaptosomal fractions of the limbic forebrain, the results might suggest that the presumably physiological enantiomer of PHN also exerts receptor blocking properties. The inhibition by (S,R)-PHN of the cocaine induced potentiation of the cyclic AMP response to NE supports this supposition. The results provide evidence that the hydroxylated metabolites of (S)-amphetamine, (S)-POH and (S,R)-PHN, modify the action of the parent drug on central noradrenergic function at the level of the NE receptor coupled adenylate cyclase system.     

Optical non-invasive technique for vessel imaging: II. A simplified photon diffusion analysis

The purpose of this paper is to explain theoretically the origin of previously presented experimental results by an optical non-invasive method using NIR for imaging blood vessels based on a specific combination of several physical parameters. The theoretical model is based on the diffusion approximation derived from the transport theory deep in a bulk tissue. An analytical solution was obtained describing photon behaviour under certain conditions during vessel identification. The modelled results indicate that the vessel identification facility depends upon source-detector separation and vessel depth, and does not depend essentially on the radiant power from the light source. The solution offers a relatively simple theoretical explanation of the experimental results and can be applied to several other clinical applications using similar technical solutions.     

The relative role of dopamine and norepinephrine receptor blockade in the action of antipsychotic drugs: Metoclopramide,thiethylperazine, and molindone as pharmacological tools

The aim of the present studies was to further delineate the role of striatal and limbic dopaminergic versus limbic noradrenergic blockade in the pharmacologic and perhaps therapeutic action of antipsychotic drugs. Metoclopramide shares many properties of antipsychotic neuroleptic drugs, including the production of extrapyramidal side effects, but is not an efficacious antipsychotic agent. This drug was a potent blocker of dopamine (DA) receptors in both striatum and limbic forebrain (comparable in potency to that of chlorpromazine) as evidenced from the increase in homovanillic acid in both brain structures. In contrast, metoclopramide was a weak inhibitor of the norepinephrine (NE) receptor-coupled adenylate cyclase system in the limbic forebrain. Molindone, which is reported not to block DA-sensitive adenylate cyclase, was a potent in vivo blocker of DA receptors in both striatum and limbic forebrain and also inhibited markedly the cyclic AMP response to NE in the limbic forebrain. The phenothiazine derivative, thiethylperazine, was also a potent blocker of DA receptors in both brain areas and displayed an IC₅₀ for NE blockade in the limbic forebrain comparable to that of chlorpromazine. The present results support the view that the ability and potency of drugs to block DA receptors parallels their ability and potency to cause extrapyramidal symptoms in man. Moreover, these results suggest that the blockade of NE receptor-coupled adenylate cyclase systems in brain may be relevant to both the pharmacologic and therapeutic activity of antipsychotic drugs.     

The serotonin/noradrenaline-link in brain

Summary The present studies were undertaken to assess the role of noradrenaline (NA) and serotonin (5HT) in the regulation of the NA receptor coupled adenylate cyclase system and its alteration by desipramine (DMI) in brain structures with or without noradrenergic neuronal projections. In contrast to cortex and limbic forebrain, where chronic DMI administration caused subsensitivity of the NA sensitive adenylate cyclase linked to a down-regulation of beta adrenoceptors, the drug failed to alter the NA receptor coupled adenylate cyclase system in the striatum. Selective lesions of serotonergic axons with 5,7-dihydroxytryptamine caused a significant increase in the density of beta adrenoceptors in cortex, limbic forebrain and striatum and prevented the down-regulation by DMI of beta adrenoceptors in cortex and limbic forebrain while the responsiveness of the NA sensitive adenylate cyclase was reduced to the same extent as in sham-lesioned control animals. The discrepancy between beta adrenoceptor number and NA responsiveness following lesions of 5HT axons was particularly profound in the striatum. The analysis of highand low-affinity components of agonist binding demonstrated that the increase in striatal beta adrenoceptors is due to a marked increase in receptors with low affinity while the number of receptors with high affinity is unchanged. The results lend further support to the view that the synaptic availability of NA is a prerequisite for the induction of subsensitivity of the NA sensitive adenylate cyclase and for the down-regulation of its beta adrenoceptor population by DMI and that 5HT plays a pivotal role in both the regulation of the number and the function of central beta adrenoceptors. Send offprint requests to F. Sulser at the above address     

Purpura annularis telangiectodes of Majocchi: case report and review of the literature

Background  Purpura annularis telangiectodes of Majocchi is an uncommon form of pigmented purpuric dermatosis which may present a therapeutic challenge. Given the rare nature of this condition, there is limited anecdotal information available regarding optimal therapy. Although pigmented purpuric dermatoses are generally innocuous, in some cases they may cause patients significant distress, and there is a need to exclude cutaneous T-cell lymphoma.
Methods  We reviewed the literature on the treatment of pigmented purpuric dermatoses and managed a 69-year-old woman who presented with purpuric annular patches on the legs.
Results  Three separate biopsies demonstrated an interstitial to perivascular lymphocytic infiltrate with erythrocyte extravasation, consistent with pigmented purpuric dermatosis. The patient's condition proved refractory to many of the previously reported modes of management, but markedly improved with methotrexate. Treatment alternatives for pigmented purpuric dermatosis are reviewed, and a treatment algorithm is proposed.
Conclusion  This is the first reported case regarding the successful use of methotrexate for pigmented purpuric dermatosis. Methotrexate may offer a therapeutic alternative to patients with highly symptomatic pigmented purpuric dermatosis refractory to other, more conservative, treatment modalities.     

Studien über frühzeitige Schädeldifformitäten

Ohne ZusammenfassungHierzu Taf. XIII–XIV.