Synthesis and Characterization of Ultra-Small Gold Nanoparticles in the Ionic Liquid 1-Ethyl-3-methylimidazolium Dicyanamide, [Emim][DCA]

We report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long-term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4  ⋅ 3 H2 O) with the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small-angle X-ray scattering (SAXS), UV-Vis spectroscopy, and MALDI-TOF mass spectrometry. A three-stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz-Slyozov-Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters.

Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics

Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D_h = 180.5 ± 5.8  nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of ζ = -43 ± 2 mV.

Automated Quantum Dots Purification via Solid Phase Extraction

The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types.

Highly Cytotoxic Osmium(II) Compounds and Their Ruthenium(II) Analogues Targeting Ovarian Carcinoma Cell Lines and Evading Cisplatin Resistance Mechanisms

(1) Background: Ruthenium and osmium complexes attract increasing interest as next generation anticancer drugs. Focusing on structure-activity-relationships of this class of compounds, we report on 17 different ruthenium(II) complexes and four promising osmium(II) analogues with cinnamic acid derivatives as O,S bidentate ligands. The aim of this study was to determine the anticancer activity and the ability to evade platin resistance mechanisms for these compounds. (2) Methods: Structural characterizations and stability determinations have been carried out with standard techniques, including NMR spectroscopy and X-ray crystallography. All complexes and single ligands have been tested for cytotoxic activity on two ovarian cancer cell lines (A2780, SKOV3) and their cisplatin-resistant isogenic cell cultures, a lung carcinoma cell line (A549) as well as selected compounds on three non-cancerous cell cultures in vitro. FACS analyses and histone γH2AX staining were carried out for cell cycle distribution and cell death or DNA damage analyses, respectively. (3) Results: IC50 values show promising results, specifically a high cancer selective cytotoxicity and evasion of resistance mechanisms for Ru(II) and Os(II) compounds. Histone γH2AX foci and FACS experiments validated the high cytotoxicity but revealed diminished DNA damage-inducing activity and an absence of cell cycle disturbance thus pointing to another mode of action. (4) Conclusion: Ru(II) and Os(II) compounds with O,S-bidentate ligands show high cytotoxicity without strong effects on DNA damage and cell cycle, and this seems to be the basis to circumvent resistance mechanisms and for the high cancer cell specificity.

Synthesis, characterization and biological investigation of platinum(ii) complexes with asparagusic acid derivatives as ligands

After more than 50 years of platinum-based anticancer research only three compounds are in clinical use worldwide. The use of the well-known lead compound of this class of anticancer agents, cisplatin, is limited by its side effects and varying resistance mechanisms. Therefore, we report on platinum(ii) compounds with asparagusic acid derivatives as ligands which show interesting anticancer results on cisplatin resistant cell lines.

Uncovering the (un-)occupied electronic structure of a buried hybrid interface

The energy level alignment at organic/inorganic (o/i) semiconductor interfaces is crucial for any light-emitting or -harvesting functionality. Essential is the access to both occupied and unoccupied electronic states directly at the interface, which is often deeply buried underneath thick organic films and challenging to characterize. We use several complementary experimental techniques to determine the electronic structure of p -quinquephenyl pyridine (5P-Py) adsorbed on ZnO(1 0   -1 0). The parent anchoring group, pyridine, significantly lowers the work function by up to 2.9 eV and causes an occupied in-gap state (IGS) directly below the Fermi level E _F. Adsorption of upright-standing 5P-Py also leads to a strong work function reduction of up to 2.1 eV and to a similar IGS. The latter is then used as an initial state for the transient population of three normally unoccupied molecular levels through optical excitation and, due to its localization right at the o/i interface, provides interfacial sensitivity, even for thick 5P-Py films. We observe two final states above the vacuum level and one bound state at around 2 eV above E _F, which we attribute to the 5P-Py LUMO. By the separate study of anchoring group and organic dye combined with the exploitation of the occupied IGS for selective interfacial photoexcitation, this work provides a new pathway for characterizing the electronic structure at buried o/i interfaces.

A Computerized Information System for a Pain Clinic

The concept of the pain clinic constitutes a recent medical development requiring a thorough documentation of patient-related data in order to achieve reasonable standards in diagnosis and treatment, to ensure that the follow-up maintains these standards and to supply necessary data for research on the epidemiology, etiology, and therapy of chronic pain. We, therefore, developed a set of medical questionnaires for pain patients together with a microcomputer system for the storage and analysis of the data obtained. The main features of our approach are the problem-oriented medical records, the multi-user system and the immediate availability of the supplied data to every therapist using the system.

Platinum(ii) O,S complexes as potential metallodrugs against Cisplatin resistance

We report on platinum(ii) complexes with different cinnamic acid derivatives as ligands with cytotoxic activity against Cisplatin resistant ovarian cancer cell line subcultures of SKOV3 and A2780. A typical mechanism of action for platinum(ii) complexes as Cisplatin itself is binding to the DNA and inducing double-strand breaks. We examined the biological behavior of these potential drugs with 9-methylguanine using NMR spectroscopic methods and their DNA damage potential including γH2AX-foci analyses. X-ray diffraction methods have been used to elucidate the molecular structures of the platinum(ii) complexes. Interactions with the model protein lysozyme have been evaluated by different techniques including UV-Vis absorption spectroscopy, fluorescence and X-ray crystallography.

Diselenolane-mediated cellular uptake

Selenophilicity, minimized dihedral angles, acidic selenols, multitarget hopping: cytosolic delivery with 1,2-diselenolanes outperforms 1,2-dithiolanes, by far.

The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

Unusual mode of protein binding by a cytotoxic π-arene ruthenium(ii) piano-stool compound containing an O,S-chelating ligand

A new π-arene Ru(ii) piano-stool compound, showing significant cytotoxic activityin vitro, was synthesized. The X-ray structure of this compound and that of its complex with RNase A were determined.

Platinum(II) Complexes with O,S Bidentate Ligands: Biophysical Characterization, Antiproliferative Activity, and Crystallographic Evidence of Protein Binding

We recently characterized a series of novel platinum(II) compounds bearing a conserved O,S binding moiety as a bifunctional ligand and evaluated their solution behavior and antiproliferative properties in vitro against a representative cancer cell line. On the whole, those platinum compounds showed an appreciable stability in mixed dimethyl sulfoxide-aqueous buffers and promising in vitro cytotoxic effects; yet they manifested a rather limited solubility in aqueous media making them poorly suitable for further pharmaceutical development. To overcome this drawback, four new derivatives of this series were prepared and characterized based on a careful choice of substituents on the O,S bidentate ligand. The solubility and stability profile of these novel compounds in a reference buffer was determined, as well as the ligands' log P(o/w) value (P(o/w) = n-octanol-water partition coefficient) as an indirect measure for the complexes' lipophilicity. The antiproliferative properties were comparatively evaluated in a panel of three cancer cell lines. The protein binding properties of the four platinum compounds were assessed using the model protein hen egg white lysozyme (HEWL), and the molecular structures of two relevant HEWL-metallodrug adducts were solved. Overall, it is shown that a proper choice of the substituents leads to a higher solubility and enables a selective fine-tuning of the antiproliferative properties. The implications of these results are thoroughly discussed.

Palliative Care teaching in Germany - concepts and future developments

BACKGROUND

Following recent modifications of the Medical Licensure Act (ÄApprO) in the year 2009, palliative care was introduced as a compulsory 13(th) cross-disciplinary subject (Q13) in the undergraduate curriculum. Its implementation must have taken place before the beginning of the final year ('practical year') in August 2013 and has to be substantiated for the medical exams taking place in October 2014. Very diverse structures pertaining to palliative care teaching were described in previous surveys at various medical faculties in Germany. As a result, the current and future plans and concepts related to content and exams of a mandatory Q13 course at the respective faculty sites should be ascertained.

METHODS

Since 2006, the German Medical Students' Association (bvmd) has been carrying out a bi-annual survey at all medical faculties in Germany regarding the current situation of teaching in the field of palliative care. After designing and piloting an online survey in May 2010, a one-month online survey took place. The data was assessed using a descriptive approach.

RESULTS

31 of 36 medical faculties took part in the survey. At the time of questioning, 15 faculties already taught courses according to the requirements of the new ÄApprO; at three sites the Q13 is yet to be introduced commencing in 2012. A teaching curriculum for Q13 already existed at 15 faculty sites, partly based on the curricular requirements of the German Association for Palliative Medicine (DGP). Six sites described an implementation process as yet without an independent curriculum. Most of the faculties aim for 21-40 course hours, which will for the most part be provided as lectures, seminars or less often in more assisted and intense formats. The majority of the participating faculties intend an examination containing multiple choice questions. At 8 universities there is an independent Chair for palliative medicine (5 more are planned); this was linked with a higher degree of mandatory teaching in alignment with the requirements of the ÄApprO. A broad spectrum of educationally-involved occupational groups, specialist disciplines and external co-operating partners, were mentioned.

CONCLUSION

The infrastructural prerequisites of the present curricular concepts and the degree of implementation of the Q13 according to the requirements of the new ÄApprO diverge significantly among the various medical faculties. The efforts made to produce a qualitatively high standard of teaching with regard to the multifaceted questions concerning the support for severely and terminally ill patients is as much reflected in the survey, as the special implications of an independent Chair for palliative medicine for the implementation of the requirements by law. The participation of various occupational groups in this survey as well as the broad spectrum of those involved highlights the interdisciplinary and multi-professional dimension of teaching in palliative care.

Gibt es einen unspezifischen Rückenschmerz?

Only 20 % of low back pain or sciatica is of a specific origin. These specific pain conditions include tumours, spondylitis, rheumatic and metabolic diseases as well as radicular syndromes. By far the most pain from discs, facet and sacroiliac joints, ligaments and muscles must be considered as unspecific, because no anamnestic information or clinical signs exist (radiological changes included) to assign pain to structural or functional correlates. In addition, the therapeutic consequences from the assignment of structural changes to pain remain unclear. In acute pain situations the specificity of the pain is not important because of the fast relief of the disease, in chronic pain situations, fear avoidance beliefs and pain behaviour seem to be much more important than structural and functional changes.

Schmerztherapeutische Angebote an Kliniken in Deutschland

Specialised pain treatment is available at inpatient, daycare and outpatient units at hospitals in Germany. A total of 579 hospitals in Germany offer at least one of the three pain treatment options. The main treatment involves outpatient care, but inpatient wards and daycare institutions have become more common. The type and number of pain treatment facilities differ regionally. Five of the 16 counties do not officially offer inpatient care at all, although pain treatment sites have been opened on the initiative of the hospitals themselves. Since specialised pain treatment is insufficiently defined by diagnosis (ICD-10) or procedures (OPS) in the German DRG system, it is not possible to recognise its availability when the facilities are not officially named. Pain treatment should be differentiated dependent on whether patients are treated within a single area of expertise or by specialised multi-professional pain facilities. At hospitals, systematic multimodal pain treatment is possible. Inpatient and daycare pain treatment programs are suitable when outpatient treatment has failed. An overview of the pain therapies offered is a prerequisite for their optimal use, the demonstration of their necessity and for their continued development throughout Germany. This study was planned and supervised by the commission for quality assurance of the German IASP chapter and was sponsored by the German IASP chapter.

Die Muskulatur als Ursache f�r R�ckenschmerzen

Lumbar muscle function is considered to be an important component of chronic low back pain (CLBP). Many studies have documented compromised muscle function in patients with CLBP. Although the mechanism associating muscle insufficiency to CLBP is not clearly understood, it is commonly held that the passive tissues of the spine are increasingly stressed with increasing functional muscle insuffiency. Functional instability of the spine plays a major role in the development of back pain. During the last few years, objective evaluation of the fatigue of back muscles by surface electromyography (EMG) with quantitative spectral techniques, evaluation of fibre type and size of the back muscles and quantifying of postural control of the lumbar spine during different tasks documented the failure of the spine in CLBP patients by a deficit of motor control more objectively. Besides this deficit, many patients show severe psychosocial problems and fear-avoidance beliefs. On this basis, treatment of CLBP with active rehabilitation, which includes educational, psychological, and social components along with the therapeutic exercises, has been increasingly advocated during recent years.

G�tekriterien der qualitativen Bewertung von Schmerzzeichnungen (Ransford-Methode) bei Patienten mit R�ckenschmerzen

BACKGROUND

The aim of our study was the analysis of the psychometric properties of the Ransford technique which is a qualitative scoring method of the pain drawing. It has been suggested that this method could be used as a brief screening technique for psychological involvement in pain complaints.

METHODS

109 patients with chronic back pain filled in the pain drawing which was rated according to the technique described by Ransford and colleagues in 1976. As external criterium of validity we chose a differentiated expert rating of psychological interference.

RESULTS

The Ransford technique showed moderate to good coefficients of reliability (re-test, inter and intra-rater). On the other hand, the Ransford technique demonstrated very low indices of validity in order to give a prognosis about psychological interference. Sensitivity and specificity of the Ransford technique demonstrated inadequate values, which furthermore were independent from cut-off points.

CONCLUSION

The pain drawing and the Ransford technique are not sufficiently sensitive and therefore allow no screening for psychological interference in complaints of back pain.

Spannungsfreie Methoden der Operation prim�rer Leistenbr�che

INTRODUCTION

Surgery of inguinal hernia has fundamentally changed since the concept of "tension-free" laparoscopic and open repair was introduced in the previous decade. Until now, final judgement of the new methods was difficult because of lack of appropriate studies.

METHODS

In a prospective clinical study, we compared the results of endoscopic, total extraperitoneal (TEP) (72 hernias) with Lichtenstein hernioplasty (66 hernias). Follow-up was done daily in the hospital and 6 weeks and 12 months after operation.

RESULTS

Operation time was equal in the case of unilateral hernias, but higher surgical qualification was required in the TEP group. Intraoperative and early postoperative complication rates were without significant difference, but late ( P=0.013) and total ( P=0.031) complication rates were significantly higher in the TEP group. There were no clear advantages for TEP in patient comfort, social criteria, or cosmetic appearance. The costs for TEP were 2,428 Euros, 440 Euros more than for the Lichtenstein operation.

CONCLUSION

As a result of the study, the Lichtenstein operation can be recommended as regular operative therapy of primary inguinal hernia because, compared with TEP, it is a simple, safe, effective and economical procedure.

[Delayed occurrence of subdural malposition of epidural catheter]

We describe a case of postoperative subdural dislocation (between dura and arachnoidea spinalis) of an epidural catheter. After 24 h of normal functioning of the catheter, the injection of 5 ml lidocaine caused an extensive unilateral sensory block including the cranial nerves. X-ray control excluded an epidural or intrathecal position of the catheter. A delayed dislocation of the epidural catheter into the subdural space can occur but this complication only usually becomes evident after injection of a normal dose of local anaesthetic into the catheter and can have catastrophic consequences. The safety of patients can only be guaranteed if epidural catheters are managed solely by professional anaesthesiological personnel. Anatomy, mechanisms of complications and clinical differential diagnosis are discussed.

[Guidelines in pain treatment--methodical quality of guidelines for treatment of pain patients]

The committee for quality assurance of the German IASP chapter (DGSS) evaluated all relevant guidelines concerning pain treatment. Quality of guidelines was analysed according to the checklist "Methodical quality of guidelines" by Ollenschläger and the user manual released by the German Medical Centre for Quality Assurance. The guideline for the treatment of back pain released by the German Medical Association was examined as well as the one released by the German Association for physical therapy and rehabilitation, the guideline on cervical and lumbal nerve root compression syndrome of the German Association of Neurosurgeons, the guideline for cancer pain of the Drug Committee of the German Medical Association was compared with the one of the German Interdisciplinary Association for Pain Treatment. The guideline for the treatment of chronic headache and facial pain of the Medical Association was evaluated and the guideline for the treatment of trigeminal neuralgia of the German Association of Neurosurgery and Neurology, also the guideline for the treatment of acute postoperative and posttraumatic pain. All guidelines show deficiencies in different aspects and of different severity. At first there are deficiencies in interdisciplinary formulation of the guidelines and identification and interpretation of evidence of multimodal pain treatment options. The most prominent deficiency is the lack of implementation and application trials or impulses by all author associations. This way all expenditure on releasing guidelines is given away without improving quality of pain treatment. The authors' recommendation is to adjust to guidelines and, if they are working or not, tell the authors and improve interdisciplinary in pain treatment guidelines.

Fear-Avoidance Behavior and Anticipation of Pain in Patients With Chronic Low Back Pain: A Randomized Controlled Study

OBJECTIVE AND DESIGN

In a randomized controlled study, we investigated whether pain anticipation and fear-avoidance beliefs will lead to behavioral avoidance.

PATIENTS

Fifty patients with chronic low back pain (CLBP) performed a simple leg-flexion task. Before the test, members of a control group were informed that the movement would not result in any increase of pain, whereas experimental group participants were told that a slight increase of pain could occur.

OUTCOME MEASURES

All patients completed the Fear-Avoidance-Beliefs Questionnaire (FABQ) and the Pain Disability Index (PDI). As dependent variables, different behavioral performance parameters were registered by a computerized protocol: number of flexion movements, mean range of motion, and mean work ratio. Furthermore, patients were asked about their pain intensity as well as their fear (at the moment) and finally were asked to judge the unpleasantness of the experiment (using visual analogue scales for each of the three variables).

RESULTS

Inducing pain anticipation (by instruction) led to significantly lower levels of behavioral performance as well as increased pain intensity and fear during the test. Behavioral performance was significantly correlated with fear-avoidance beliefs.

CONCLUSIONS

Results confirm that pain anticipation and fear-avoidance beliefs significantly influence the behavior of patients with low back pain in that they motivate avoidance behavior. Therapists must be aware of the powerful effects of cognitive processes, which can give rise to fear of pain and, consequently, avoidance behavior.

[Relevance of nerve blocks in treating and diagnosing low back pain--is the quality decisive?]

Diagnostic nerve blocks: The popularity of neural blockade as a diagnostic tool in painful conditions, especially in the spine, is due to features like the unspecific character of spinal pain, the irrelevance of radiological findings and the purely subjective character of pain. It is said that apart from specific causes of pain and clear radicular involvement with obvious neurological deficits and corresponding findings of a prolapsed disc in MRI or CT pictures, a diagnosis of the anatomical cause of the pain can only be established if invasive tests are used [5]. These include zygapophyseal joint blocks, sacroiliacal joint blocks, disc stimulation and nerve root blocks. Under controlled conditions, it has been shown that among patients with chronic nonradicular low back pain, some 10-15% have zygapophyseal joint pain [58], some 15-20% have sacroiliacal joint pain [36, 59] and 40% have pain from internal disc disruption [60]. The diagnostic use of neural blockade rests on three premises. First, pathology causing pain is located in an exact peripheral location, and impulses from this site travel via a unique and consistent neural root. Second, injection of local aneasthetic totally abolishes sensory function of intended nerves and does not affect other nerves. Third, relief of pain after local anaesthetic block is attributable solely to block of the target afferent neural pathway. The validity of these assumptions is limited by complexities of anatomy, physiology, and psychology of pain perception and the effect of local anaesthetics on impulse conduction [28]. Facet joints: The prevalence of zygapophyseal joint pain among patients with low back pain seems to be between 15% and 40% [62], but apparently only 7% of patients have pure facet pain [8, 29]. Facet blockade is achieved either by injection of local anaesthetic into the joint space or around the medial branches of the posterior medial rami of the spinal nerves that innervate the joint. There are several problems with intraarticular facet injections, mainly failure to enter the joint capsule and rupture of the capsule during the injection [11]. There is no physiological means to test the adaequacy of medial nerve block, because the lower branches have no cutaneous innervation. Medial ramus blocks (for one joint two nerves have to be infiltrated) are as effective as intraarticular joint blocks [37]. Reproducibility of the test is not high, the specifity is only 65% [61]. For diagnosis of facet pain fluoroscopic control is always necessary as in the other diagnostic blocks. Sacroiliacal joint: Definitely the sacroiliacal joint can be the source of low back pain. Stimulation of the joint by injection in subjects without pain produces pain in the buttock, in the posterior thigh and the knee. There are many clinical tests which confirm the diagnosis, but the interrater reliability is moderate [53]. Intraarticular injection can be achieved in the lower part of the joint with fluoroscopic guidance only, but an accurate intraarticular injection, which is confirmed by contrast medium, even at this place is often difficult. It is not clear whether intraarticular spread is necessary to achieve efficacy. Discography: Two primary syndromes concerning the ventral compartment have been described: anular fissures of the disc and instability of the motion segment. In the syndrome of anular tear, leakage of nucleus pulposus material into the anulus fibrosus is considered to be the source of pain. The studies of Vaharanta [71] and Moneta [41] show a clear and significant correlation between disc pain and grade 3 fissures of the anulus fibrosus. intervertebral discs are difficult to anaesthetize. Intradiskal injections of local anaesthetics may succeed in relieving the patient's pain, but such injections are liable to yield false negative results if the injected agent fails to adequately infiltrate the nerve endings in the outer anulus fibrosus that mediate the patient's pain. In the majority of cases MRI provide adaequate information, but discography may be superior in early stages of anular tear and in clarifying the relation between imaging data and pain [71]. Selective spinal nerve injection: In patients with complicated radiculopathy, the contribution of root inflammation to pain may not be certain, or the level of pathology may be unclear. Diagnostic root blocks are indicated in the following situations: atypical topography of radicular pain, disc prolapses or central spinal stenosis at more than one level and monoradicular pain, lateral spinal stenosis, postnucleotomysyndrome. Injection of individual spinal nerves by paravertebral approach has to be used to elucidate the mechanism and source of pain in this unclear situations. The premise is that needle contact will identify the nerve that produces the patient's characteristic pain and that local anaesthetic delivered to the pathogenic nerve will be uniquely analgesic. Often, this method is used for surgical planning, such as determining the site of foraminotomy. All diagnostic nerve root blocks have to be done under fluoroscopic guidance. Pain relief with blockade of a spinal nerve cannot distinguish between pathology of the proximal nerve in the intervertebral foramen or pain transmitted from distal sites by that nerve. Besides, the tissue injury in the nerve's distribution and neuropathic pain (for instance as a result of root injury) likewise would be relieved by a proximal block of the nerve. Satisfactory needle placement could not be achieved in 10% of patient's at L4, 15% at L5 and 30% at S1 [28]. The positive predictive value of indicated radiculopathy confirmed by surgery ranged between 87-100% [14, 22]. The negative predictive value is poorly studied, because few patients in the negative test group had surgery. Negative predictive values were 27% and 38% of the small number of patients operated on despite a negative test. Only one prospective study was published, which showed a positive predictive value of 95% and an untested negative predictive value [66]. Some studies repeatedly demonstrated that pain relief by nerve root block does not predict success by neuroablative procedures, neither by dorsal rhyzotomy nor by dorsal gangliectomy [46]. Therapeutic nerve blocks - facet joints: Intraarticular injection of steroids offer no greater benefit than injections of normal saline [8, 15] and long lasting success is lacking. In this case, a denervation of the medial branches can be considered. To date three randomized controlled studies of radiofrequency facet denervation have been published. One study [20] reported only modest outcomes and its results remained inconclusive, another study [72] with a double blind controlled design showed some effects in a small selected group of patients (adjusted odds ratio 4.8) 3, 6 and 12 months after treatment, concerning not only reduction of pain but alleviating functional disability also. The third study (34a) showed no effect 3 months after treatment. Discogenic pain: Intradiscal radiofrequency lesions, intradiscal injections of steroids and phenol have been advocated, but there are no well controlled studies. Just recently, intradiscal lesion and denervation of the anulus has been described with promising results, but a randomized controlled study is lacking up to now [31, 55]. Epidural Steroids: Steroids relieve pain by reducing inflammation and by blocking transmission of nociceptive C-fiber input. Koes et al. [33] reviewed the randomized trials of epidural steroids: To date, 15 trials have been performed to evaluate the efficacy, 11 of which showed method scores of 50 points (from 100) ore more. The trials showed inconsistent results of epidural injections. Of the 15 trials, 8 reported positive results and 7 others reported negative results. Consequently the efficacy of epidural steroid injections has not yet been established. The benefits of epidural steroid injections seem to be of short duration only. Future efficacy studies, which are clearly needed, should take into account the apparent methological shortcomings. Furthermore, it is unclear which patients benefit from these injections. In our hands the injection technique can be much improved by fluoroscopic guidance of the needle, with a prone position of the patient, and lateral injection at the relevant level and with a small volume (1-2 ml) and low dose of corticosteroid (20 mg triamcinolone in the case of a monoradicular pain, for example). In the case of epidural adhesions in postoperative radicular pain [50], the study of Heafner showed that the additional effect of hyaloronidase and hypertonic saline to steroids was minimal. In our hands there was no effect in chronic radicular pain 3 months after the injection.

Back pain, the uncomfortable truth - assurance and activity problem

Back problems are common, expensive, and the few patients who are the crux of the problem are uncomfortable but also an uncomfortable frustration for clinicians and employers alike. We now know that clinicians can greatly improve the patient's response to back symptoms by admitting our diagnostic limitations, demedicalizing the issue, providing assurance, and encouraging a more reasonable approach to improving comfortable activity tolerance.

Determination of regional ventilation and perfusion in the lung using xenon and computed tomography

We propose a model to measure both regional ventilation (V) and perfusion (Q) in which the regional radiodensity (RD) in the lung during xenon (Xe) washin is a function of regional V (increasing RD) and Q (decreasing RD). We studied five anesthetized, paralyzed, mechanically ventilated, supine sheep. Four 2.5-mm-thick computed tomography (CT) images were simultaneously acquired immediately cephalad to the diaphragm at end inspiration for each breath during 3 min of Xe breathing. Observed changes in RD during Xe washin were used to determine regional V and Q. For 16 mm(3), Q displayed more variance than V: the coefficient of variance of Q (CV(Q)) = 1.58 +/- 0.23, the CV of V (CV(V)) = 0.46 +/- 0.07, and the ratio of CV(Q) to CV(V) = 3.5 +/- 1.1. CV(Q) (1.21 +/- 0.37) and the ratio of CV(Q) to CV(V) (2.4 +/- 1.2) were smaller at 1,000-mm(3) scale, but CV(V) (0.53 +/- 0.09) was not. V/Q distributions also displayed scale dependence: log SD of V and log SD of Q were 0.79 +/- 0.05 and 0.85 +/- 0.10 for 16-mm(3) and 0.69 +/- 0.20 and 0.67 +/- 0.10 for 1,000-mm(3) regions of lung, respectively. V and Q measurements made with CT and Xe also demonstrate vertically oriented and isogravitational heterogeneity, which are described using other methodologies. Sequential images acquired by CT during Xe breathing can be used to determine both regional V and Q noninvasively with high spatial resolution.

[Treatment of chronic low back pain through intensive activation - an assessment of 10 years]

AIM OF THE STUDY

Treatment of chronic low back pain is a difficult problem and usually of low effectiveness. Aim of the study was to analyse the effectiveness of a multimodal treatment procedure.

METHODS

From the basis of functional restoration concepts primarily established in the USA we conceptualized a treatment program which initially was funded by the German ministry of research. Over the years the regimen was modified in several respects (programs of different intensity). From 1990 to 2000 762 patients were treated in this way with one-year follow-up examination.

RESULTS

Patients who were off work had significant differences in psychosocial and pain-related variables in comparison to those patients who were still working. Treatment procedures were in general very effective, although a modification of the program with less treatment (no work-hardening) failed in repeating the same effects. Pain intensity, disability, amount of depression and psychological distress improved significantly as well as work capability and use of the health care system. Nearly all results were seen to stabilize at the 12-month evaluation.

DISCUSSION

Functional restoration programs for treatment of chronic low back pain have demonstrated effectiveness in several countries. By early use of these programs the high amount of costs due to back pain disability may be consequently reduced. Up to now in Germany these concepts are not well-known and insurance companies as well as the health system do not yet acknowledge them.

Muscarinic receptors of the M2 subtype in human and bovine trabecular meshwork

BACKGROUND

The trabecular meshwork is a tissue actively involved in the regulation of intraocular pressure via contractile mechanisms. The present study was performed to investigate the effects of muscarinic m2-receptor antagonists on trabecular meshwork contractility and to identify the m2 muscarinic receptor in human and bovine trabecular meshwork cells.

METHODS

Isometric tension measurements of bovine trabecular meshwork strips were performed using a custom-made force length transducer. Western blot and immunoprecipitation analysis was used to detect the m2-receptor proteins in membrane preparations of human and bovine trabecular meshwork cells.

RESULTS

Immunoblotting results showed the expression of an m2-receptor protein band at 56 kDa in both human and bovine trabecular meshwork cells. Two different m2-receptor antagonists were tested on trabecular meshwork contractility. After carbachol-induced contraction (10(-6) M set to 100% contractile force), specific m2-receptor antagonists were applied. 3 alpha-Chloroimperaline (10(-6) M) had no effect on the maximal carbachol-induced contraction in trabecular meshwork strips. Methoctramine induced a significant relaxation at concentrations of 10(-7), 10(-6) and 5 x 10(-6) M even in the presence of m1- and m3-receptor antagonists.

CONCLUSION

These data indicate that in addition to the m3-receptor subtype present in the trabecular meshwork this tissue also features the m2 receptor. This receptor is partly involved in the regulation of trabecular meshwork contractility, suggesting that outflow facility might be influenced through this receptor.

Validation of the German version of the Fear-Avoidance Beliefs Questionnaire (FABQ)

Fearful avoidance of physical activities is a major factor in low back pain (LBP) and disability. In 1993 Waddell et al. developed the Fear-Avoidance Beliefs Questionnaire (FABQ) focusing on patients' beliefs about how physical activity and work affect LBP. The focus of our study was to analyse and validate the German version of the FABQ. Three-hundred and two consecutive LBP outpatients participating on a functional restoration programme filled in the FABQ. Factor analysis yielded three factors which accounted for nearly 65% of the total variance of the questionnaire. Whereas the factor 'physical activity' (8.9% of the variance) remained the same as in the English version, the second factor of the original version split into two: one related to, 'work as cause of pain' (43.4% of the variance) and the other to patients' assumptions of their probable return to work (11.8% of the variance). Both work-related subscales showed a good internal consistency (alpha = 0.89, resp. alpha = 0.94), whereas the consistency of the subscale 3 'physical activity' was only modest (alpha = 0.64). Test-re-test reliability score was fair to good for the whole scale (r = 0.87;n = 30). Regression analysis demonstrated that fear-avoidance beliefs account for the highest proportion of variance (35%) regarding disability in activities of daily living and work loss. Patients out of work demonstrated more fear-avoidance beliefs in comparison to those who were still working. It can be concluded that the German version of the FAQB is a reliable and valid instrument, but it shows a different factor structure from the original English version. The FABQ has been proven to identify patients with maladaptive beliefs which have to be focused on in proper treatment.

Ventilation heterogeneity in excised lobes: effect of tidal volume

Although several factors are known to influence nonuniformity of ventilation, including lung mechanical properties (regional structure and compliance), external factors (chest wall, pleural pressure, heart), and ventilatory parameters (tidal and preinspiratory volume, flow rate), their relative contributions are poorly understood. We studied five excised, unperfused, canine right-middle lobes under varied levels of tidal volume (VT), thus eliminating many factors affecting heterogeneity. Multiple-breath washouts of N(2) were analyzed for anatomic dead space volume (VD(anat)), nonuniformity of N(2) washout, and nonuniformity between joined acinar regions vs. that occurring between larger joined regions. Approximately 80% of ventilation heterogeneity was found among joined acinar regions at resting levels of VT, but increasing VT reduced intra-acinar heterogeneity to about 25% of that found at resting levels. Increasing VT had essentially no effect on VD(anat) and heterogeneity among larger joined regions. The results indicate that the magnitude of VT is a major influence on the dominant intra-acinar component of ventilation heterogeneity and that VT effects on VD(anat) are likely due to perfusion and/or influences normally external to the lobar structure.

Gravitational effects on volume distribution in a model of partial and total liquid ventilation

To estimate regional lung volume during ventilation with liquids (e. g. perfluorochemicals, PFC) we developed a multi-compartment mathematical model of a lung and thorax. The height of the fluid column and the fluid's density determine alveolar pressure (PA). The weight of thoracic contents above any given gravitational plane influences pleural pressure (PPL). Transpulmonary pressure (PTP=PA−PPL) and compliance of the lung and chest wall permit estimation of volumes. The results indicate the lung inflates almost uniformly during total liquid ventilation despite a substantial vertical PA gradient. Inflation uniformity is due to the offsetting vertical PPL gradient created by the added weight of the PFC and sustained by the relative rigidity of the chest wall. During partial liquid ventilation our model indicates that the combination of uniform PA with a large vertical gradient in PPL leads to a vertical PTP gradient and therefore relative over-inflation of the top of the lung. This effect increases with increasing PFC dose and with lung height.