Biomedical subjects

M Schäfer

Publications and source records attributed to M Schäfer.

At least 19 recordsLinked to original sources

PubMed2007

[Experience with new teaching methods and testing in psychiatric training].

In 1999, the Charité Medical University in Berlin, Germany, implemented a reformed medical study course (RMSC) along with traditional undergraduate medical education. The RMSC is characterized by problem-based learning (PBL), training in communication skills with "simulated patients", and interdisciplinary seminars. The curriculum is organized into blocks according to organ system and age (period od life). In a new intensive 4-week psychiatric block, 4th-year students get practical experience in psychiatric wards. Furthermore, PBL groups and workshops are offered that focus on frequent psychiatric disorders. By providing interactive courses with simulated patients, students are intensively trained in taking psychiatric histories and in generating psychopathological findings. Defined learning objectives are tested using multiple-choice items and objectively structured clinical examinations at semester end. First positive results indicate that this course represents an appropriate and practicable curriculum for teaching psychiatry in Germany.

Education, Medical↗

PubMed2006

Interleukin-1 beta contributes to the upregulation of kappa opioid receptor mrna in dorsal root ganglia in response to peripheral inflammation.

During local painful inflammation, axonal transport of opioid receptors from dorsal root ganglia toward the periphery is increased, associated with a higher receptor density and enhanced efficacy of opioid analgesics at the injured site. To examine whether this increase is related to transcription, mRNA of the kappa opioid receptor in lumbar dorsal root ganglia was quantified by real time light cycler polymerase chain reaction. In dorsal root ganglia of naive rats, kappa opioid receptor mRNA expression was three-fold higher than previously shown for delta opioid receptor and two times lower than mu opioid receptor mRNA, respectively. After induction of unilateral paw inflammation by Freund's complete adjuvant, kappa opioid receptor mRNA was significantly upregulated with a peak at 12 h in ipsilateral dorsal root ganglia. This effect could be mimicked by intraplantar injection of the proinflammatory cytokine interleukin-1 beta. Kappa opioid receptor mRNA upregulation lasted longer in interleukin-1 beta-treated rats compared with Freund's complete adjuvant-treated rats. Furthermore, a significant increase in kappa opioid receptor positive neurons was detected by immunohistochemistry 24 h after local injection of Freund's complete adjuvant or interleukin-1 beta. In Freund's complete adjuvant-induced inflammation, kappa opioid receptor upregulation was blocked by treatment with interleukin-1 receptor antagonist without changing the leukocyte infiltration in the paw. In conclusion, kappa opioid receptor mRNA and protein in dorsal root ganglia are upregulated in response to peripheral inflammation. This effect can be mimicked by a single local injection of interleukin-1 beta, and Freund's complete adjuvant-induced upregulation in kappa opioid receptor mRNA and protein can be prevented by treatment with interleukin-1 receptor antagonist. These data suggest that the peripheral production of the proinflammatory cytokine interleukin-1 beta is a specific inducer of kappa opioid receptor expression in the dorsal root ganglia.

Animals↗

PubMed2006

Invarioms for improved absolute structure determination of light-atom crystal structures.

The determination of molecular absolute configuration from an X-ray analysis for structures that contain only light elements is challenging owing to the weak anomalous dispersion signal. The achievable precision of the Flack x parameter for such structures is therefore limited, especially when the independent-atom model is employed. Invariom modelling can improve this situation. Invarioms are theoretically predicted pseudoatoms within the Hansen & Coppens multipole formalism. They are transferable from one molecule to another and provide generalized aspherical atomic form factors. It is shown that, by application of the invariom approach, the precision and standard uncertainty of the Flack x parameter and therefore the reliability of deducing molecular chirality in an absolute structure determination can be improved.

Crystallography, X-Ray↗

PubMed2006

[Septic thrombosis of the axillary vein with unilateral pulmonary abscess. Variation of Lemierre's syndrome].

HISTORY: A man aged 62 was hospitalized for treatment of an axillary abscesses originating from a suppurative hidradenitis. INVESTIGATIONS: Microbiological tests revealed peptostreptococcus and staphylococci. Hepatic enzymes were moderately elevated in association with a mild hyperbilirubinemia. RESULTS: After surgical intervention the patient developed a severe septic illness together with a unilateral pulmonary infection and abscess formation, requiring a thoracotomy. Preoperative serology ruled out active hepatitis as well as atypical pneumonia. The detection of a unilateral septic axillary thrombosis led to the correct diagnosis. Antibiotics and anticoagulation brought about a complete cure. CONCLUSION: In cases of septicemia of uncertain origin septic venous thromboses should be considered in the differential diagnosis.

Anti-Bacterial Agents↗

PubMed2006

Direct observation of the Aharonov-Casher phase.

Ring structures fabricated from HgTe/HgCdTe quantum wells have been used to study Aharonov-Bohm type conductance oscillations as a function of Rashba spin-orbit splitting strength. We observe nonmonotonic phase changes indicating that an additional phase factor modifies the electron wave function. We associate these observations with the Aharonov-Casher effect. This is confirmed by comparison with numerical calculations of the magnetoconductance for a multichannel ring structure within the Landauer-Büttiker formalism.

Journal Article↗

PubMed2006

[Relevance of childhood trauma for later drug dependence].

UNLABELLED: There are various publications on the impact of the experience of violence and abuse during childhood as it relates to future substance abuse. This study aims to examine how childhood abuse differentiated by type and severity, impacts on future potential for substance abuse. Particular attention is paid to specific psychological symptoms and degree of addiction. METHODS: 100 patients being treated for substance abuse completed a questionnaire where they were questioned about a childhood history of sexual, physical and emotional abuse, neglect and family violence. Psychopathology and severity of addiction were assessed using the EuropASI and SCL-90. RESULTS: The results demonstrated that the respondents had been exposed to multiple risk factors in their childhood. The subjects were differentiated into groups according to type of abuse. The type and severity of psychological symptoms were measured by the SCL-90-R. The type and severity of psychosocial and environmental problems were measured by the EuropASI. It was shown that patients with a history of abuse had a significantly higher incidence of symptomatology, particularly of co-morbid psychological conditions. When differentiating victims of abuse by sex, women showed a significantly stronger impairment in 2 categories. These were insecurity in social contact and phobic fear. For all other variables of impairment, there were no differences between men and women. The severity of the various types of abuse was then correlated to the course of the disease. A strong correlation was found between severe forms of abuse where victims were involved in sexual abuse or family violence and future severe psychological symptoms.

Adult↗

PubMed2006

[New aspects in postoperative pain therapy].

This review summarizes and critically appraises important and clinically relevant publications dealing with postoperative pain therapy. Several consequences can be drawn from these studies: i) women anticipate postoperative pain more realistically and it occurs more often than in man; however, pain intensity and analgesic consumption are not different; ii) placebos elicit psychological phenomena (e. g. expectation) that trigger neurobiological processes (e. g. activation of endogenous opioid system); iii) COX-2 inhibitors increase the risk for thromboembolic complications (e. g. myocardial infarction, apoplex, pulmonary embolism) and perioperative mortality in patients undergoing aortocoronary bypass surgery; iv) NSAID as supplement to postoperative PCIA with opioids reduce the risk for PONV and sedation; v) preoperative administration of gabapentin reduces preoperative anxiety and postoperative pain; vi) epidural catheters situated at the site of major spinal surgery are promising approach to provide efficient postoperative analgesia; vii) in the literature contradictory results have been reported regarding the effect of perioperative acupuncture on intra- and postoperative consumption of anesthetics or analgesics; acupuncture appears to decrease the incidence of PONV, but no reduction in the postoperative use of antiemetic agents has not been shown yet; viii) laparoscopic versus open colectomy in patients with colon carcinoma results in prolongation of surgery, reduction of postoperative pain and analgesics, earlier mobilization and a reduced hospital stay, if conventional systemic opioid-based pain therapy was used postoperatively.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

[Current diagnosis and treatment of pancreatic cancer].

Adenocarcinoma of the pancreas (pancreatic cancer) is the most frequent tumor entity in the pancreas. While the results of surgical therapy of pancreatic cancer were disappointing in the past due to high perioperative mortality rates, resection of pancreatic cancer nowadays represents the standard treatment for non-metastatic cancer with a mortality rate below 5%. This decrease in perioperative mortality of the Whipple operation is inversely correlated to the case load of the hospital and the responsible surgeon, and is mainly related to improvements in the intensive care management, the surgical technique and patient selection. In particular, the perioperative use of octreotide resulted in a significant decrease in the rate of pancreatic fistula. Furthermore, modern staging examinations such as diagnostic laparoscopy, PET, or endoscopic ultrasound resulted in improved patient selection. In addition, the long-term results of the surgical treatment of pancreatic cancer has been improved by adjuvant and neoadjuvant chemotherapy in the past 10 years. Similar progress has been made in the palliative treatment of metastatic or locally advanced cancer. Nowadays, endoscopic procedures can replace surgical palliation of obstructive jaundice in most cases and sometimes even gastric outlet obstruction. Moreover, systemic chemotherapy using gemcitabine-based protocols has resulted in a significant prolongation of survival. However, further progress in the treatment of pancreatic cancer can only be achieved by an interdisciplinary management of this disease.

Adenocarcinoma↗

PubMed2005

Mechanism of cGMP-mediated protection in a cellular model of myocardial reperfusion injury.

OBJECTIVE: Reperfusion injury of the myocardium is characterised by development of cardiomyocyte hypercontracture. Previous studies have shown that cGMP-mediated stimuli protect against reperfusion injury, but the cellular mechanism is still unknown. METHODS: To simulate ischemia/reperfusion, adult rat cardiomyocytes were incubated anoxically (pH(o) 6.4) and then reoxygenated (pH(o) 7.4). Cytosolic calcium [Ca(2+)](i) (fura-2 ratio), pH(i) (BCECF ratio), cell length, and phospholamban phosphorylation were analysed. Under simulated ischemia cardiomyocytes develop [Ca(2+)](i) overload. When reoxygenated they rapidly undergo hypercontracture, triggered by oscillations of [Ca(2+)](i). We investigated whether cGMP-mediated stimuli can modulate [Ca(2+)](i) or pH(i) recovery and whether this contributes to their protective effect. Membrane-permeable cGMP analogues, 8-bromo-cGMP (1 mmol/L) or 8-pCPT-cGMP (10 micrommol/L), or a receptor-mediated activator of particulate guanylyl cyclase, urodilatin (1 micromol/L), were applied. RESULTS: The investigated stimuli protect against reoxygenation-induced hypercontracture (cell length as percent of end-ischemic length; control: 68+/-1.6; 8-bromo-cGMP: 88+/-1.5*; 8-pCPT-cGMP: 84+/-2.9*; urodilatin: 87+/-1.1*; n=24; *p<0.05). Recovery from [Ca(2+)](i) overload after 2 min reoxygenation [fura-2 ratio (a.u.); control: 1.43+/-0.15; 8-bromo-cGMP: 1.86+/-0.15*; 8-pCPT-cGMP: 1.92+/-0.19*; urodilatin: 1.93+/-0.24*; n=25; *p<0.05] was accelerated, and the frequency of [Ca(2+)](i) oscillations (min(-1)) was significantly reduced (control: 49+/-5.0 min(-1); 8-bromo-cGMP: 18+/-3.5* min(-1); 8-pCPT-cGMP: 18+/-4.5* min(-1); urodilatin: 16+/-4.1* min(-1); n=24; *p<0.05). cGMP-mediated stimuli increased sarcoplasmic Ca(2+) sequestration (caffeine-releasable Ca(2+) pool: 2-3 fold increase vs. control). Inhibition of sarcoplasmic Ca(2+)-ATPase (SERCA) by thapsigargin (150 nmol/L) or of protein kinase G with KT-5823 (1 micromol/L) abolished the effect of these stimuli on [Ca(2+)](i) recovery. The investigated stimuli significantly enhanced phospholamban phosphorylation. CONCLUSIONS: We conclude that cGMP-dependent signals activate SERCA via a protein kinase G-dependent phosphorylation of phospholamban. The increase in SERCA activity seems to reduce peak [Ca(2+)](i) and [Ca(2+)](i) oscillation during reoxygenation and to attenuate the excessive activation of the contractile machinery that otherwise leads to the development of hypercontracture.

Animals↗

PubMed2005

[Critical reevaluation of cyclooxygenase two inhibitors in perioperative pain therapy].

A significant increase in thromboembolic events (i.e. myocardial infarction and stroke) was demonstrated in multicenter studies after several months of treatment with cyclooxygenase 2 (cox-2) inhibitors. In February 2005, the European medical agencies (EMEA) substantially increased the number of contraindications for all cox-2 inhibitors. They are now contraindicated for patients with coronary artery disease. Furthermore, 2 out of 6 cox-2 inhibitors have been withdrawn from the market. In this review, the current state of knowledge on the use of cox-2 inhibitors in perioperative pain therapy is summarized: i) they are equally as potent as other non-opioid analgesics, ii) they decrease opioid consumption, iii) a reduction in postoperative nausea and vomiting (PONV) has not been adequately demonstrated. Regarding side-effects, it can be concluded that i) the incidence of thromboembolic events is increased in patients undergoing coronary artery bypass surgery, ii) perioperative blood loss is not affected, iii) ulcer formation is not promoted, iv) the risk for acute renal failure is probably increased to the same extent as for NSAIDs and v) severe bronchospasm can be triggered in patients with asthma and chronic obstructive pulmonary disease (COPD).

Contraindications↗

PubMed2005

[New concept minimizes bleeding in radical retropubic prostatectomy].

BACKGROUND: Radical retropubic prostatectomy is an intervention known to be associated with severe bleeding. Even experienced surgeons report a blood transfusion rate of up to 20%. The perioperative concept for this intervention underwent various modifications in January 2001. This study describes the effect of these modifications on the blood loss in a retrospective analysis comparing approximately 100 operations by a single experienced surgeon before the change (group 1) with 100 operations thereafter (group 2). MATERIALS AND METHODS: The new perioperative concept comprised the following points: reducing the intravenously applied volume, employing a peridural catheter (PDC), and maintaining a 25-30 degrees Trendelenburg's position. The difference in pre- and postsurgical hemoglobin (Hb) was analyzed before (group 1) and after the intervention (group 2). If transfusions were performed, this value was corrected according to the following formula: 1 ml of erythrocyte concentrate increases the patient's Hb by 0.003 g/dl. RESULTS: Assessment was possible in 201 of 234 cases, 110 from the first and 91 from the second group. The mean transfusion-corrected Hb difference was 5.3 g/dl in group 1 (20% transfusion rate) and 3.52 g/dl in group 2 (1.09% transfusion rate); p>0.0001. The median intravenous volume applied was 5.960 ml in group 1 and 3.490 ml in group 2 (p>0.0001). The complication rate did not differ between groups. CONCLUSION: The new perioperative concept minimizes the intraoperative blood loss during radical open retropubic prostatectomy. Transfusions are only necessary in rare cases. The complication rate remains unaltered.

Blood Loss, Surgical↗

PubMed2005

[Topical application of local anesthetics and opioids after elective tooth extraction].

The aim of this study was to provide evidence for the peripheral effect of opioids in oromaxillary procedures and to investigate whether postoperative morphine sulfate plus lidocaine administered as a local spray achieve better analgesic efficacy than lidocaine applied alone. The double-blind randomized study included 60 patients. The patients exhibited neither preoperative pain nor inflammation (tooth extractions) and when pain occurred received as alternative medication diclofenac retard 50 mg or tramadol. Side effects were documented. No differences between the two groups were observed in the demographic data, visual and numeric analog scale in the first 24 h, or in the consumption of analgesics. Since the patients presented in a pain-free state at the time of surgery, apparently no activation of the peripheral opioid receptors occurs. Thus, a peripheral effect of opioids could not be demonstrated in this model.

Administration, Topical↗

PubMed2005

[Potential applications and significance of peripheral opioid analgesia].

Recently, the local application of analgesic substances has attracted much interest and has become increasingly relevant in daily clinical practice. The lack of the well-known therapy-limiting central side effects of systemically administered opioids is a clear advantage of "peripheral opioid analgesia". Important prerequisites for the occurrence of peripheral analgesic effects of opioids are good accessibility of the painful site, presence of clinically relevant pain, signs of a local inflammation, exclusion of a fast systemic absorption, and adequately potent analgesic substances. This review gives an outline of recent experience with various clinical applications of "peripheral opioid analgesia".

Analgesics, Opioid↗

PubMed2005

["Highlights" in emergency medicine -- severe head trauma, polytrauma and cardiac arrest].

According to scientific publications focusing on emergency medicine and published in international journals in the past few months, new and clinically important results can be identified. In patients with severe head trauma (SHT), application of hypertonic solutions is possible; long term outcome, however, is not improved by this measure. Prehospital capnometry is important, because otherwise up to 40 % of all mechanically ventilated patients are hypoventilated. In a study in 200 patients with prehospital cardiac arrest and ventricular fibrillation as initial cardiac rhythm, subgroup analysis (alarm-response time > 5 min) showed an increase in survival rate (14 % vs. 2 %), if defibrillation was proceeded by 3 min of conventional cardiopulmonary resuscitation (CPR) for reperfusion. If ACD ("active compression decompression")-CPR is combined with a specific ventilatory valve ("inspiratory impedance threshold device", ITD) which does not allow passive inspiration, survival rate after cardiac arrest is increased for up to 24 h. Such a device facilitates an increase in venous return to the heart during decompression of the thorax. High-dose adrenalin for intrahospital CPR in children is not associated with better survival but with worse outcome. Comparison of an emergency medical service (EMS) system from U.K. with paramedics and a physician-staffed German EMS system demonstrated that survival rate following prehospital cardiac arrest is markedly increased with doctors on board. The European multicentre trial comparing vasopressin vs. adrenalin as first vasopressor during CPR in 1219 patients did not reveal any differences between both groups. In subgroup analyses of patients with asystoly and prolonged CPR, vasopressin was superior without being associated with a benefit on neurological outcome. Further subgroup analyses revealed beneficial effects of amiodarone and thrombolysis during CPR. Thrombolysis during CPR apears to be associated with an increased rate of haemodynamic stabilisation without increased risk of bleeding complications. In a very clear advisory statement, the "International Liaison Committee on Resuscitation" (ILCOR) has recommended mild therapeutic hypothermia (i. e., cooling of cardiac arrest victims to 32 - 34 degrees C central body temperature for 12 - 24 h following cardiac arrest of cardiac etiology) not only for unconciuous patients with ventricular fibrillation as initial prehospital rhythm, but also for all other adult patients (other rhythms, intrahospital CPR) following cardiac arrest. In randomised controlled clinical trials, this therapy has markedly improved survival rate and neurological outcome. Such therapeutic cooling can be initiated nearly everywhere and with simple methods - like the infusion of ice-cold cristalloid solutions.

Cardiopulmonary Resuscitation↗

PubMed2005

[New osteosynthesis techniques for the treatment of distal femoral fractures].

The treatment of distal femoral fractures was for a long-time associated with high complication rates. Although implants and surgical techniques were improved, plate osteosynthesis and intramedullary nailing suffered from considerable rates of infection, non-union und malalignment. Attention to the soft tissue envelope by "biological" osteosynthesis and minimally invasive approaches resulted in decreased complication rates. Out of this movement grew the concept of minimal invasive plating with an internal fixator -- the LISS-DF (Less Invasive Stabilization System -- Distal Femur) -- and the retrograde nailing concept. This article should give a review about these two new techniques for the treatment of distal femoral fractures. Indications, the clinical use and the aftercare will be discussed.

Bone Plates↗

PubMed2005

[Catecholamine-resistant hypotension -- an update].

Vasoplegia as catecholamine resistent hypotension occurs in severe hemorrhagic or septic shock and post cardiopulmonary bypass. The entire rational behind this phenomenon is still unclear. An ATP-shortage in the vascular musculature, disregulation of vasopressin release, and the activation of ATP-dependent potassium-channels are discussed. In the last years, attention is drawn towards the activation of ATP-dependent potassium-channels and the possible therapeutic inhibition by glibenclamid. However, inhibition of potassium-channels does not normalize blood pressure under all circumstances. In particular in septic shock other mechanisms have to be involved. Overall, the sometimes desperate clinical situation has led to a large number of case reports und uncontrolled series of retrospectively analysed cases, where vasopressin or methylenblue were discribed as successfully reversing catecholamine resistent hypotension. Nevertheless, in hemorrhagic and septic shock scientific evidence of the clinical effects and the right dose as well as placebo controlled studies comparing the agents and possible combinations of agents are desirable but hardly available yet. In the case of severe hypotension following surgery under cardiopulmonary bypass results of the first randomized and placebo controlled studies describe successful restoration of blood pressure and even a decrease in perioperative mortality. Concerning the side effects, vasopressin and methylenblue, like most vasopressors, can cause gastrointestinal ischemia, but with the small number of patients enrolled so far, further major side effects can not be ruled out. Accordingly, the identification of risk factors for the development of vasoplegia and the prediction of the extent of the response or the rate of non-responders to these treatments are widely unknown. However, although the administration of vasopressin and methylenblue can not be recommended as a standard treatment it provides an additional option in individual cases of life threatening vasoplegia.

ATP-Binding Cassette Transporters↗

PubMed2005

Safety of one-stage bilateral hip and knee arthroplasties under regional anaesthesia and routine anaesthetic monitoring.

Using a computer-based quality assurance program, we analysed peri-operative data on 160 patients undergoing one-stage bilateral hip or knee arthroplasties under regional anaesthesia with routine anaesthetic monitoring and only using peripheral intravenous access for peri-operative safety. We monitored defined intra-operative adverse events such as hypotension, myocardial ischaemia, arrhythmias, hypovolaemia, hypertension and early post-operative complications. We also determined post-operative hip and knee function, and patient satisfaction with different aspects of the anaesthetic management. Those patients undergoing one-stage bilateral arthroplasties were matched according to a cross-stratification which used three variables (American Society of Anesthesiologists' physical status scoring system, age and joint replaced) to patients undergoing unilateral hip or knee arthroplasties. Serious intra-operative adverse events were, with the exception of intra-operative hypotension, very infrequent in patients undergoing bilateral (nine adverse events) as well as unilateral arthroplasties (five adverse events). Early post-operative complications were also infrequent in both groups. However, the risks of receiving a heterologous blood transfusion (odds ratio 2.5; 95% confidence interval (CI) 1.3 to 5.0, estimated by exact conditional logistic regression) or vasoactive drugs (odds ratio 3.9; 95% CI 2.0 to 7.8) were significantly greater for patients undergoing bilateral operations. Patient satisfaction with anaesthesia was high; all patients who underwent the one-stage bilateral operation would choose the same anaesthetic technique again.

Aged↗

PubMed2005

Abundance and diversity of human-biting flies (Diptera: Ceratopogonidae, Culicidae, Tabanidae, Simuliidae) around a nickel-copper smelter at Monchegorsk, northwestern Russia.

In the summers of 2001 and 2002, we quantitatively sampled human-biting flies in twelve sites located 1.6 to 63 km from a large copper-nickel smelter at Monchegorsk on the Kola Peninsula, Russia. We collected 429 specimens of three species of Ceratopogonidae, 92 specimens of seven species of Culicidae, 76 specimens of seven species of Tabanidae, and 4,788 specimens of 19 species of Simuliidae. Culicoides chiropterus was for the first time reported from the Kola Peninsula. Catches of Culicidae and Simuliidae decreased near the smelter, presumably due to the combined action of toxicity of pollutants, pollution-induced forest damage, and decline in vertebrate density. An abundance of Ceratopogonidae and Tabanidae, the size of the most common black fly species, Simulium pusillum, and the diversity of all families did not change along the pollution gradient.

Animals↗