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Biomedical subjects

Andreas Meissner

Publications and source records attributed to Andreas Meissner.

6 recordsLinked to original sources
PubMed2006

Merkel cell carcinoma -- a rarity in the urogenital tract.

BACKGROUND: Merkel cell carcinoma -- a rare, aggressive cancer of the skin integument - is being increasingly diagnosed but represents an absolute rarity in the urogenital tract. CASE REPORT: We report on a 70-year-old man who was referred to us with suspected testicular cancer. The pathology report revealed a metastasized Merkel cell carcinoma. Fulminant disease progression under chemo-therapy (regimen as for small cell lung cancer) resulted in death 5 months later. CONCLUSION: The patient described is considered to be the first to develop testicular metastasis derived from Merkel cell carcinoma. Besides neuroendocrine and epithelial antigen tests, somatostatin receptor scintigraphy is a helpful diagnostic tool. New receptor-associated therapies may allow more effective and less toxic treatment modalities in the mostly elderly or immune deficient patients.

Aged↗
PubMed2006

[Preoperative stratification of risks in patients with disorders of the cardiovascular system].

Disorders of the cardiovascular system are among the most important accompanying diseases in operative medicine. These diseases increase the perioperative risk; the risk is assessed on the basis of the case history and tolerance of the patient as well as the extent and invasiveness of the surgical intervention. Depending on the results of this stratification further examination and therapy may be necessary. The aim of these mainly preventative measures is the highest possible preoperative hemodynamic stability. Besides pharmacological prevention, a therapy for hypertension or ischemia belongs among these measures. The selected anesthesia process must guarantee and efficient prevention of pain.

Anesthesia↗
PubMed2005

Recent developments in beta-blockers and anaesthesia.

PURPOSE OF REVIEW: To evaluate developments on the subject of beta-blockers and anaesthesia published in the past 12 months. The administration of beta-blockers has been established as a pharmacological approach to reduce cardiac events in the perioperative period. A number of studies and reviews have been published underlining the appropriateness of this approach in patients undergoing non-cardiac as well as cardiac surgery. A lack of transfer of the scientific knowledge to clinical practice is evident not only in the field of perioperative medicine, which results in an under-use of beta-blockers. Open questions are still directed towards the optimal dosage, the effectiveness of chronic beta-blockade and the effects of beta-blockade in traumatized and burned patients. RECENT FINDINGS: Progress in the use of beta-blockers has been realized by the introduction of institutional protocols. In chronic beta-blockade a simple continuation does not provide effective protection. Improved protection might be gained by the combination of beta-blockers and statins in high-risk patients. The role of beta-blockers in pain management is currently a field of interest, although there seem to be many open questions. There are still doubts about the evidence of perioperative beta-blockade: the results of large trials will be published in the next 2 years. The approach is cost-effective: a comparison with other alternative approaches to cardioprotection is pending. SUMMARY: There has been significant progress in the use of perioperative beta-blockade. Although a considerable amount of knowledge is obvious, the optimal strategy in different clinical settings is still a matter of debate.

Journal Article↗
PubMed2003

In vivo recording of monophasic action potentials in awake dogs.

Assessment of cardiac repolarization in dogs in vivo is of interest in numerous experimental canine models. Previous studies have used monophasic action potentials (MAPs) to investigate repolarization in vitro and in vivo in anesthetized animal models. Therefore, an approach for recording MAPs in awake dogs without the interference of anesthesia is desirable. We describe an experimental technique to record MAPs in conscious dogs by means of conventional rubber introducers which are implanted into the internal jugular vein. Atrial as well as ventricular MAPs can be simultaneously measured without complications. Pacing thresholds are low and stable over time. Continuous MAP recordings of stable amplitude can be achieved from the same endocardial site for periods up to 1h. Antegrade and retrograde atrioventricular nodal conduction properties can be assessed. Programmed stimulation can be performed to simultaneously determine local refractory periods and MAP duration at cycle lengths from 500 to 200ms. In awake, unsedated dogs measuring MAPs via rubber introducers permits safe, long-term recording of MAPs. Such recordings may be useful for safety pharmacologic studies in evaluating cardiovascular and noncardiovascular drugs with respect to their effects on repolarization. In various canine in vivo models including in vivo models of long QT syndrome, heart failures or sudden cardiac death, the present technique permits electrophysiologic measurements without the interference of anesthesia.

Action Potentials↗
PubMed2002

Naloxone improves splanchnic perfusion in conscious dogs through effects on the central nervous system.

BACKGROUND: In patients undergoing colonoscopy, naloxone has vasodilative properties. However, it remains unclear whether this effect is mediated by central or peripheral mechanisms. The aim of this study was to investigate whether these effects are mediated by an effect of naloxone on the central nervous system. METHODS: Twenty dogs were chronically instrumented for measurement of hemodynamic parameters. Splanchnic blood flow was determined using colored microspheres. Transthoracic echocardiographic examinations were performed to measure cardiac output. In each animal, two experiments were performed in a random order: experiment 1 was determination of splanchnic blood flow before and 5 min after intravenous administration of naloxone (63 microg/kg), and experiment 2 was determination of splanchnic blood flow before and 5 min after administration of naloxone methiodide (63 microg/kg), which does not cross the blood-brain barrier. RESULTS: Naloxone, but not naloxone methiodide, significantly increased blood flow to the stomach (from 0.41 +/- 0.022 to 0.9 +/- 0.016# ml x g (-1) x min(-1) with naloxone), jejunum (from 0.31 +/- 0.024 to 0.83 +/- 0.083# ml x g(-1) x min(-1) with naloxone), colon (from 0.41 +/- 0.057 to 0.68 +/- 0.008# ml x g(-1) x min(-1) with naloxone), spleen (from 1.45 +/- 0.21 to 2.13 +/- 0.25# ml x g(-1) x min(-1) with naloxone), pancreas (from 0.97 +/- 0.021 to 1.25 +/- 0.005# ml x g(-1) x min(-1) with naloxone), and kidneys (from 3.24 +/- 0.108 to 5.31 +/- 0.26# ml x g(-1) x min(-1) with naloxone), without altering cardiac output or arterial blood pressure in conscious dogs. There were no differences in the hemodynamics or cardiac output between the two experiments. Data are presented as mean +/- SD. CONCLUSIONS: The increased splanchnic perfusion after naloxone is not caused by direct peripheral vascular effects or increased cardiac output. Indirect vasodilative effects on splanchnic vessels mediated by actions of naloxone on the central nervous system account for the increased gastrointestinal perfusion after naloxone in dogs.

Animals↗