[Analgesic Drug Therapy in Kidney Patients]. / Schmerzmedikamente bei Nierenpatienten.

Analgesic drug therapy in kidney patients needs special expertise. Patients with kidney disease frequently have pain and they have chronic pain more than others. Some analgesic drugs have a nephrotoxic potential and co-analgesics such as anticonvulsive, antidepressive and antipsychotic drugs need a dose adjustment to kindey function. When treating kidney patients with morphine, the accumulation kinetics of the M6 glucuronide must be observed. Otherwise, the risk increases for respiratory depression.

[Carpal tunnel syndrome: correlation between median nerve relative constriction in the carpal tunnel and distal motor latency]. / Karpaltunnelsyndrom: Korrelation zwischen der relativen Einengung des N. medianus im Karpalkanal und der distalen motorischen Latenz.

PURPOSE: This study analyses the correlation between the constriction in the substance of the median nerve in the carpal tunnel and distal motor latency, gender and age of patients with a carpal tunnel syndrome. PATIENTS AND METHODS: In 82 patients (59 women and 23 men with an average age of 66.6 (41-89) years) with an electrophysiologically verified carpal tunnel syndrome undergoing open carpal tunnel release, the diameter of the median nerve was measured at the narrowest point of the nerve at the level of the constriction and the widest point of the nerve proximal to the constriction. The grade of nerve constriction was the ratio between the diameter at the level of the constriction and the widest diameter proximal to the constriction. Additionally, the distance from the distal wrist crease to the beginning of the constriction was measured. The grade of constriction was correlated with the patients' distal motor latency, gender and age. RESULTS: The diameter of the median nerve at the narrowest point of the constriction averaged 6.0 (SD 1.1) mm; the diameter at the widest point proximal to the constriction was 7.6 (SD 1.5) mm. The distance from the distal wrist crease to the beginning of the constriction averaged 17.6 (SD 3.7) mm. Grade of nerve constriction did not correlate with distal motor latency. However, there was a correlation between patient age and distal motor latency. CONCLUSION: The grade of nerve constriction cannot be estimated based on the severity of prolongation of distal motor latency. There is a positive correlation between the age of patients with a carpal tunnel syndrome and distal motor latency.

Bee Stings and Chronic Pain Disorder.

Chronic pain is a major problem of public health, and patients seek manifold forms of help to find relief. Here we present and discuss the case of a middle-aged woman suffering from mental disorders who treated her headache with the self-application of bee stings on her back.

The role of periaqueductal gray and cingulate cortex during suppression of pain in complex regional pain syndrome.

OBJECTIVE: Complex regional pain syndrome I (CRPS I) is a frequent and debilitating condition with unclear etiology. Hypothesizing that maladaptive central processes play a crucial role in CRPS, the current study set out to explore cerebral activation during a task to suppress the feeling of pain under constant painful stimulation. METHODS: Ten individuals with CRPS I with symptoms on their left hand were subjected to electrical stimulation of both index fingers subsequently in a functional magnetic resonance imaging experiment. Their data were compared with 15 healthy controls. RESULTS: Concerning psychophysical measures, patients succeeded similarly as healthy controls in suppressing the feeling of pain. However, during constant painful stimulation and with the task to suppress the feeling of pain, there were significant differences in the interaction analyses of the corresponding cortical activation. DISCUSSION: Patients differ from healthy controls by the activation pattern of cerebral areas that belong to the descending opioid pain suppression pathway: PAG and cingulate cortex are activated significantly less during suppression of pain, regardless of whether the symptomatic or asymptomatic hand was stimulated. Thus, there is a generalized functional change in individuals with CRPS I. However, it cannot be deducted whether the abnormality is causative or merely an effect, possibly maladaptive.

Different activation of opercular and posterior cingulate cortex (PCC) in patients with complex regional pain syndrome (CRPS I) compared with healthy controls during perception of electrically induced pain: a functional MRI study.

OBJECTIVES: Although the etiology of complex regional pain syndrome type 1 (CRPS 1) is still debated, many arguments favor central maladaptive changes in pain processing as an important causative factor. METHODS: To look for the suspected alterations, 10 patients with CRPS affecting the left hand were explored with functional magnetic resonance imaging during graded electrical painful stimulation of both hands subsequently and compared with healthy participants. RESULTS: Activation of the anterior insula, posterior cingulate cortex (PCC), and caudate nucleus was seen in patients during painful stimulation. Compared with controls, CRPS patients had stronger activation of the PCC during painful stimulation of the symptomatic hand. The comparison of insular/opercular activation between controls and patients with CRPS I during painful stimulation showed stronger (posterior) opercular activation in controls than in patients. DISCUSSION: Stronger PCC activation during painful stimulation may be interpreted as a correlate of motor inhibition during painful stimuli different from controls. Also, the decreased opercular activation in CRPS patients shows less sensory-discriminative processing of painful stimuli.These results show that changed cerebral pain processing in CRPS patients is less sensory-discriminative but more motor inhibition during painful stimuli. These changes are not limited to the diseased side but show generalized alterations of cerebral pain processing in chronic pain patients.

The effects of thoracic epidural anesthesia on hepatic blood flow in patients under general anesthesia.

BACKGROUND: Hepatic hypoperfusion is regarded as an important factor in the pathophysiology of perioperative liver injury. Although epidural anesthesia (EDA) is a widely used technique, no data are available about the effects on hepatic blood flow of thoracic EDA with blockade restricted to thoracic segments in humans. METHODS: In 20 patients under general anesthesia, we assessed hepatic blood flow index in the right and middle hepatic vein by use of multiplane transesophageal echocardiography before and after induction of EDA. The epidural catheter was inserted at TH7-9, and mepivacaine 1% with a median (range) dose of 10 (8-16) mL was injected. Norepinephrine (NE) was continuously administered to patients who demonstrated a decrease in mean arterial blood pressure below 60 mm Hg after induction of EDA (EDA-NE group). The other patients did not receive any catecholamine during the study period (EDA group). A further 10 patients without EDA served as controls (control group). RESULTS: In five patients, administration of NE was necessary to avoid a decrease in mean arterial blood pressure below 60 mm Hg. Thus, the EDA-NE group consisted of five patients and the EDA group of 15. In the EDA group, EDA was associated with a median decrease in hepatic blood flow index of 24% in both hepatic veins (P < 0.01). In the EDA-NE group, all five patients showed a decrease in the blood flow index of the right (median decrease 39 [11-45] %) and middle hepatic vein (median decrease 32 [7-49] %). Patients in the control group showed a constant blood flow index in both hepatic veins. Reduction in blood flow index in the EDA group and the EDA-NE group was significant in comparison with the control group (P < 0.05). In contrast to hepatic blood flow, cardiac output was not affected by EDA. CONCLUSIONS: We conclude that, in humans, thoracic EDA is associated with a decrease in hepatic blood flow. Thoracic EDA combined with continuous infusion of NE seems to result in a further decrease in hepatic blood flow.

A prospective randomized trial comparing traditional and fast-track patient care in elective open infrarenal aneurysm repair.

BACKGROUND: Fast-track recovery programs have led to reduced patient morbidity and mortality after major surgery. In terms of elective open infrarenal aneurysm repair, no evidence is available about such programs. To address this issue, we have conducted a randomized prospective pilot study. METHODS: The study involved prospective randomization of 101 patients with the indication for elective open aneurysm repair in a traditional and a fast-track treatment arm. The basic fast-track elements were no bowel preparation, reduced preoperative fasting, patient-controlled epidural analgesia (PCEA), enhanced postoperative feeding, and postoperative mobilization. Morbidity and mortality, need for postoperative mechanical ventilation, length of stay (LOS) in the intensive care unit (ICU) and total length of postoperative hospital stay were analyzed in terms of an intention to treat. RESULTS: Demographic data for the two groups were similar. In the fast-track group the need for postoperative ventilation was significantly lower (6.1% versus 32%; p = 0.002), the median LOS on ICU did not significantly differ (20 h versus 32 h; p = 0.183), full enteral feeding was achieved significantly earlier (5 versus 7 days; p < 0.0001), and the rate of postoperative medical complications-gastrointestinal, cardiac, pulmonary, renal, and infective-was significantly lower (16% versus 36%; p = 0.039). The postoperative hospital stay was significantly shorter in the fast-track group (10 days versus 11 days; p = 0.016); the mortality rate in both groups was 0%. CONCLUSIONS: An optimized patient care program in open infrarenal aortic aneurysm repair shows favorable results concerning need for postoperative assisted mechanical ventilation, time to full enteral feeding, and incidence of medical complications. Further ranomized multicentric trials are necessary to justify broad implementation (clinical trials. gov identifier NCT 00615888).

Reduction of postoperative pulmonary complications after lung surgery using a fast track clinical pathway.

BACKGROUND: Fast track programs, multimodal therapy strategies, have been introduced in many surgical fields to minimize postoperative morbidity and mortality. In terms of lung resections no randomized controlled trials exist to evaluate such patient care programs. METHODS: In a prospective, randomized controlled pilot study a conservative and fast track treatment regimen in patients undergoing lung resections was compared. Main differences between the two groups consisted in preoperative fasting (6h vs 2h) and analgesia (patient controlled analgesia vs patient controlled epidural analgesia). Study endpoints were pulmonary complications (pneumonia, atelectasis, prolonged air leak), overall morbidity and mortality. Analysis was performed in an intention to treat. RESULTS: Both study groups were similar in terms of age, sex, preoperative forced expiratory volume in one second (FEV(1)), American Society of Anesthesiologists score and operations performed. The rate of postoperative pulmonary complications was 35% in the conservative and 6.6% in the fast track group (p=0.009). A subgroup of patients with reduced preoperative FEV(1) (<75% of predicted value) experienced less pulmonary complications in the fast track group (55% vs 7%, p=0.023). Overall morbidity was not significantly different (46% vs 26%, p=0.172), mortality was comparable in both groups (4% vs 3%). CONCLUSION: We evaluated an optimized patient care program for patients undergoing lung resections in a prospective randomized pilot study. Using this fast track clinical pathway the rate of pulmonary complications could be significantly decreased as compared to a conservative treatment regimen; our results support the implementation of an optimized perioperative treatment in lung surgery in order to reduce pulmonary complications after major lung surgery.

Prospective randomized controlled trial to evaluate "fast-track" elective open infrarenal aneurysm repair.

BACKGROUND AND AIMS: Fast-track programs have been introduced in many surgical fields to minimize postoperative morbidity and mortality. Morbidity after elective open infrarenal aneurysm repair is as high as 30%; mortality ranges up to 10%. In terms of open infrarenal aneurysm repair, no randomized controlled trials exist to introduce and evaluate such patient care programs. MATERIALS AND METHODS: This study involved prospective randomization of 82 patients in a "traditional" and a "fast-track" treatment arm. Main differences consisted in preoperative bowel washout (none vs. 3 l cleaning solution) and analgesia (patient controlled analgesia vs. patient controlled epidural analgesia). Study endpoints were morbidity and mortality, need for postoperative mechanical ventilation, and length of stay (LOS) on intensive care unit (ICU). RESULTS: The need for assisted postoperative ventilation was significantly higher in the traditional group (33.3% vs. 5.4%; p = 0.011). Median LOS on ICU was shorter in the fast-track group, 41 vs. 20 h. The rate of postoperative medical complications was significantly lower in the fast-track group, 16.2% vs. 35.7% (p = 0.045). CONCLUSION: We introduced and evaluated an optimized patient care program for patients undergoing open infrarenal aortic aneurysm repair which showed a significant advantage for "fast-track" patients in terms of postoperative morbidity.

Validation of a raw data-based synchronization signal (kymogram) for phase-correlated cardiac image reconstruction.

Phase-correlated reconstruction is commonly used in computed tomography (CT)-based cardiac imaging. Alternatively to the commonly used ECG, the raw data-based kymogram function can be used as a synchronization signal. We used raw data of 100 consecutive patient exams to compare the performance of kymogram function to the ECG signal. For objective validation the correlation of the ECG and the kymogram was assessed. Additionally, we performed a double-blinded comparison of ECG-based and kymogram-based phase-correlated images. The two synchronization signals showed good correlation indicated by a mean difference in the detected heart rate of negligible 0.2 bpm. The mean image quality score was 2.0 points for kymogram-correlated images and 2.3 points for ECG-correlated images, respectively (3: best; 0: worst). The kymogram and the ECG provided images adequate for diagnosis for 93 and 97 patients, respectively. For 50% of the datasets the kymogram provided an equivalent or even higher image quality compared with the ECG signal. We conclude that an acceptable image quality can be assured in most cases by the kymogram. Improvements of image quality by the kymogram function were observed in a noticeable number of cases. The kymogram can serve as a backup solution when an ECG is not available or lacking in quality.

pknotsRG: RNA pseudoknot folding including near-optimal structures and sliding windows.

RNA pseudoknots are an important structural feature of RNAs, but often neglected in computer predictions for reasons of efficiency. Here, we present the pknotsRG Web Server for single sequence RNA secondary structure prediction including pseudoknots. pknotsRG employs the newest Turner energy rules for finding the structure of minimal free energy. The algorithm has been improved in several ways recently. First, it has been reimplemented in the C programming language, resulting in a 60-fold increase in speed. Second, all suboptimal foldings up to a user-defined threshold can be enumerated. For large scale analysis, a fast sliding window mode is available. Further improvements of the Web Server are a new output visualization using the PseudoViewer Web Service or RNAmovies for a movie like animation of several suboptimal foldings. The tool is available as source code, binary executable, online tool or as Web Service. The latter alternative allows for an easy integration into bio-informatics pipelines. pknotsRG is available at the Bielefeld Bioinformatics Server (http://bibiserv.techfak.uni-bielefeld.de/pknotsrg).

[Phantom limb pain]. / Phantomschmerz--Diagnostik und Therapie--Erinnerungen an nicht mehr vorhandene Körperteile beeinflussen.

Almost everyone who has amputated a limb will experience a phantom limb. They have the vivid impression, that the limb is still present. 60 to 70% of these amputees will suffer from phantom limb pain. The present paper gives an overview of the incidence and the characteristics of the so called "post amputation syndrome". Possible mechanism of this phenomena are presented, including peripheral, spinal, and central theories. Treatment of phantom limb pain is sometimes very difficult. It includes drug therapy, psychological therapy, physiotherapy as well as the prevention of phantom limb pain with regional analgesia techniques.

RNAshapes: an integrated RNA analysis package based on abstract shapes.

We introduce RNAshapes, a new software package that integrates three RNA analysis tools based on the abstract shapes approach: the analysis of shape representatives, the calculation of shape probabilities and the consensus shapes approach. This new package is completely reimplemented in C and outruns the original implementations significantly in runtime and memory requirements. Additionally, we added a number of useful features like suboptimal folding with correct dangling energies, structure graph output, shape matching and a sliding window approach.

Versatile and declarative dynamic programming using pair algebras.

BACKGROUND: Dynamic programming is a widely used programming technique in bioinformatics. In sharp contrast to the simplicity of textbook examples, implementing a dynamic programming algorithm for a novel and non-trivial application is a tedious and error prone task. The algebraic dynamic programming approach seeks to alleviate this situation by clearly separating the dynamic programming recurrences and scoring schemes. RESULTS: Based on this programming style, we introduce a generic product operation of scoring schemes. This leads to a remarkable variety of applications, allowing us to achieve optimizations under multiple objective functions, alternative solutions and backtracing, holistic search space analysis, ambiguity checking, and more, without additional programming effort. We demonstrate the method on several applications for RNA secondary structure prediction. CONCLUSION: The product operation as introduced here adds a significant amount of flexibility to dynamic programming. It provides a versatile testbed for the development of new algorithmic ideas, which can immediately be put to practice.

Effective ambiguity checking in biosequence analysis.

BACKGROUND: Ambiguity is a problem in biosequence analysis that arises in various analysis tasks solved via dynamic programming, and in particular, in the modeling of families of RNA secondary structures with stochastic context free grammars. Several types of analysis are invalidated by the presence of ambiguity. As this problem inherits undecidability (as we show here) from the namely problem for context free languages, there is no complete algorithmic solution to the problem of ambiguity checking. RESULTS: We explain frequently observed sources of ambiguity, and show how to avoid them. We suggest four testing procedures that may help to detect ambiguity when present, including a just-in-time test that permits to work safely with a potentially ambiguous grammar. We introduce, for the special case of stochastic context free grammars and RNA structure modeling, an automated partial procedure for proving non-ambiguity. It is used to demonstrate non-ambiguity for several relevant grammars. CONCLUSION: Our mechanical proof procedure and our testing methods provide a powerful arsenal of methods to ensure non-ambiguity.

Fast and effective prediction of microRNA/target duplexes.

MicroRNAs (miRNAs) are short RNAs that post-transcriptionally regulate the expression of target genes by binding to the target mRNAs. Although a large number of animal miRNAs has been defined, only a few targets are known. In contrast to plant miRNAs, which usually bind nearly perfectly to their targets, animal miRNAs bind less tightly, with a few nucleotides being unbound, thus producing more complex secondary structures of miRNA/target duplexes. Here, we present a program, RNA-hybrid, that predicts multiple potential binding sites of miRNAs in large target RNAs. In general, the program finds the energetically most favorable hybridization sites of a small RNA in a large RNA. Intramolecular hybridizations, that is, base pairings between target nucleotides or between miRNA nucleotides are not allowed. For large targets, the time complexity of the algorithm is linear in the target length, allowing many long targets to be searched in a short time. Statistical significance of predicted targets is assessed with an extreme value statistics of length normalized minimum free energies, a Poisson approximation of multiple binding sites, and the calculation of effective numbers of orthologous targets in comparative studies of multiple organisms. We applied our method to the prediction of Drosophila miRNA targets in 3'UTRs and coding sequence. RNAhybrid, with its accompanying programs RNAcalibrate and RNAeffective, is available for download and as a Web tool on the Bielefeld Bioinformatics Server (http://bibiserv.techfak.uni-bielefeld.de/rnahybrid/).

Bacterial contamination of epidural catheters: microbiological examination of 502 epidural catheters used for postoperative analgesia.

STUDY OBJECTIVE: To investigate the frequency of bacterial colonization of epidural catheters used for postoperative pain treatment longer than 24 hours in abdominal, thoracic, or trauma surgery patients. DESIGN: Retrospective study. SETTING: Intermediate care facility and general ward of a university hospital. PATIENTS: 502 patients who received epidural catheters after abdominal, thoracic, or vascular surgery at our institution from January 1996 to December 2000. INTERVENTIONS: Placement of an epidural catheter, which was used for postoperative pain treatment, for more than 24 hours. The puncture site dressing included saturation each day with povidone-iodine. MEASUREMENTS AND MAIN RESULTS: Microbiologic monitoring of epidural catheter tips and daily examination of puncture sites with regard to signs of inflammation took place. Four times daily patients were examined to check adequacy of pain treatment and neurologic deficits. Catheter tip cultures were positive in 29 patients (5.8%). Staphylococcus epidermidis was isolated in 22 cases (76%). No case of spinal epidural abscess was observed within 6 months after epidural catheterization. The average catheterization time was 5 days (quartile range: 4 to 6 days). CONCLUSIONS: Meticulous management ensures a relatively low level of bacterial contamination in epidural catheters applied for postoperative pain treatment greater than 5 days. Contamination rarely leads to spinal epidural infection.