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Biomedical subjects

D Irnich

Publications and source records attributed to D Irnich.

9 recordsLinked to original sources
PubMed2003

Characterization of neuronal nicotinic acetylcholine receptors in the membrane of unmyelinated human C-fiber axons by in vitro studies.

Application of acetylcholine to peripheral nerve terminals in the skin is a widely used test in studies of human small-fiber functions. However, a detailed pharmacological profile and the subunit composition of nicotinic acetylcholine receptors in human C-fiber axons are not known. In the present study, we recorded acetylcholine-induced changes of the excitability and of the intracellular Ca2+ concentration in C-fiber axons of isolated human nerve segments. In addition, using immunohistochemistry, an antibody of a subtype of nicotinic acetylcholine receptor was tested. Acetylcholine and agonists reduced the current necessary for the generation of action potentials in C fibers by > 5-Iodo-A-85380 > 1,1-dimethyl-4-phenylpiperazinium iodide > nicotine > cytisine > acetylcholine; choline had no effect. The epibatidine-induced increase in axonal excitability was blocked by mecamylamine and, less efficiently, by methyllycacontine and dihydro-beta-erythroidine. Many C-fiber axons were labeled by an antibody that recognizes the alpha5 subunit of nicotinic acetylcholine receptors. In summary, electrophysiological and immunohistochemical data indicate the functional expression of nicotinic acetylcholine receptors composed of alpha3, alpha5, and beta4 but not of alpha4/beta2 or of alpha7 subunits in the axonal membrane of unmyelinated human C fibers. In addition, the observations suggest that the axonal membrane of C fibers in isolated segments of human sural nerve can be used as a model for presumed cholinergic chemosensitivity of axonal terminals.

Action Potentials↗
PubMed2003

[Central anticholinergic syndrome and apnea after general anaesthesia. A rare manifestation of the central anticholinergic syndrome].

The central anticholinergic syndrome (CAS) is a rarely observed condition after general anaesthesia. There are no definitive criteria to set the diagnosis of CAS. The syndrome may manifest in clinical neurological signs, such as hyperactive states or a depressed CNS state. The diagnosis usually depends on a process of exclusion of other conditions and is confirmed after rapid recovery following administration of physostigmine. We report on a 34-year-old patient who suddenly lost consciousness and developed respiratory arrest 1 h after general anesthesia and normal postoperative recovery. CAS was considered, although apnea has not been reported as a clinical symptom of this disease up to now and no peripheral signs of CAS were observed. After the administration of 1 mg physostigmine the symptoms resolved immediately and the patient started sufficient spontaneous breathing. However, corresponding to the plasma elimination half-life of the drug, further comatose episodes with apnea occurred. Therefore, the patient was admitted to the ICU and an infusion of physostigmin at a rate of up to 5 mg/h was started. Due to this therapy the patient's state became stable and 15 h after the first manifestation of CAS the infusion of physostigmin was discontinued. The following postoperative course was uneventful. In case of reduced vigilance with apnea after general anaesthesia, central anticholinergic syndrome should be considered. For diagnostic and therapeutic purposes the administration of physostigmine should be attempted.

Adult↗
PubMed2003

Acupuncture Randomized Trials (ART) in patients with chronic low back pain and osteoarthritis of the knee - design and protocols.

BACKGROUND: We report on the study design and protocols of two randomized controlled trials (Acupuncture Randomized Trials = ART) that investigate the efficacy of acupuncture in the treatment of chronic low back pain and osteoarthritis of the knee, respectively. OBJECTIVE: To investigate whether acupuncture is more efficacious than (a) no treatment or (b) minimal acupuncture in the treatment of low back pain and osteoarthritis. DESIGN: Two randomized, controlled, multicenter trials with three treatment arms and a total follow-up time of 52 weeks. SETTING: 30 practitioners and outpatient units in Germany specialized in acupuncture treatment. PATIENTS: 300 patients will be included in each study. In the low back pain trial, patients will be included according to clinical diagnosis. In the osteoarthritis pain trial, patients will be included according to the American College of Rheumatology criteria. INTERVENTIONS: Patients are randomly assigned to receive either (1) semi-standardized acupuncture (150 patients), (2) minimal acupuncture at non-acupuncture points (75 patients), or (3) no treatment for two months followed by semi-standardized acupuncture (75 patients, waiting list control). Acupuncture treatment consists of 12 sessions per patient over a period of 8 weeks. MAIN OUTCOME MEASURE: The main outcome measure is the difference between baseline and the end of the 8-week treatment period in the following parameters: pain intensity as measured by a visual analogue scale (VAS; 0-100 mm) in the low back pain trial and by the Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC) in the osteoarthritis trial. OUTLOOK: The results of these two studies (available in 2004) will provide health care providers and policy makers with the information needed to make scientifically sound assessments of acupuncture therapy.

Acupuncture Therapy↗
PubMed2002

[Electric stimulation acupuncture in peripheral neuropathic pain syndromes. Clinical pilot study on analgesic effectiveness].

AIM: The aim of this pilot study was to investigate the potential value of acupuncture in the treatment of peripheral neuropathic pain. Explorative analysis should provide data for further randomised controlled trials. METHOD: In an uncontrolled clinical trial electroacupuncture was given to 17 patients with chronic neuropathic pain of peripheral origin which was resistant to preceding pain therapy. Patients were treated twice weekly for 4 weeks. Assessment of outcome measurements comprised: Intensity of continuous pain (visual analogue scale, VAS), intensity of pain attacks (VAS), duration of pain attacks, number of pain attacks and changes in mood (VAS). All measures were evaluated by diary (1 week before treatment to 2 weeks after treatment and 1 week at follow up three months after treatment). Changes of global complaints and patients' beliefs in treatment (credibility assessment) were also assessed. RESULTS: At re-evaluation two weeks after treatment, mean continuous pain was reduced by 32.9% and intensity of pain attacks was reduced by 59%. Mean number of daily pain attacks decreased from 4.2 (SD +/- 4.6, 0.14-13.3) before treatment to 2.2 (SD +/- 3.8, 0-7.5) two weeks after treatment. Duration of pain attacks and mood showed no substantial changes. Three months after treatment, continuous pain was reduced by 15.9% and intensity of pain attacks was reduced by 44% compared to baseline. No serious adverse events were observed CONCLUSIONS: On the basis of this small pilot study, trial treatment by electroacupuncture seems to be justified in these patients given a lack of success of standard treatments. The apparent beneficial analgesic effects of electroacupuncture appear to warrant further investigation.

Acupuncture Analgesia↗
PubMed2002

[Neurobiological mechanisms of acupuncture analgesia].

AIM: The aim of this review is to present the findings of basic research about mechanism of acupuncture-induced analgesia (AA) on the basis of the relevant literature. The transferability of the results into practice and theory of traditional acupuncture are critically discussed. METHOD: Extensive literature research was used to identify and summarize relevant studies. RESULTS: AA has been proven by biochemical, immunohistochemical, molecular biological and neurophysiological investigations. It has been shown that short term AA is mediated by an activation of endogenous antinociceptive systems and descending inhibitory systems. Long term effects cannot be explained sufficiently by experimental results; however, they suggest an involvement of long term inhibitory synaptic modification at spinal cord neurons and clinical and radiological findings indicate limbic system modulation. CONCLUSION: Regarding the complexity of endogenous pain-inhibitory systems and the methodological shortcomings many questions remain unanswered. Further research activities are necessary in this field.

Acupuncture Analgesia↗
PubMed2002

ATP stimulates peripheral axons in human, rat and mouse--differential involvement of A(2B) adenosine and P2X purinergic receptors.

Receptors for ATP have been reported on peripheral nerve terminals. It is a widespread assumption that the axonal membrane does not possess this kind of chemosensitivity, although P2X purinoceptors have been found in isolated rat vagus nerve. Therefore, in the present study, effects of ATP and analogues were tested on the excitability of unmyelinated axons in isolated rat sural nerve, mouse dorsal roots, and human sural nerve. Bath application of ATP to all three types of axonal preparations increased axonal excitability, but the underlying receptors appear to differ in the various preparations. In rat sural nerve, alpha,beta-adenosine-5'-methylene triphosphate produced the strongest excitation. This effect was blocked by pyridoxal-phosphate-6-azophenyl-2',5'-disulphonic acid and indicates the presence of P2X receptors. In mouse dorsal roots, differences were found between fast and slow C-fibres. The latter responded to both P2X receptor and adenosine receptor agonists. In contrast, effects of ATP on faster-conducting C-fibres seem to be caused exclusively by effects of ATP on adenosine receptors. Application of ATP also excited C-fibres in fascicles of isolated human nerve. The pharmacological profile indicates activation of A(2B) adenosine receptors. However, we could not detect P2X receptors in this preparation with our techniques. These data show that the ATP sensitivity of sensory neurones is not restricted to their terminals. Activation of axonal purinergic receptors may contribute to the transduction of sensory, including nociceptive, stimuli.

Adenosine Triphosphate↗
PubMed2001

Randomised trial of acupuncture compared with conventional massage and "sham" laser acupuncture for treatment of chronic neck pain.

OBJECTIVES: To compare the efficacy of acupuncture and conventional massage for the treatment of chronic neck pain. DESIGN: Prospective, randomised, placebo controlled trial. SETTING: Three outpatient departments in Germany. PARTICIPANTS: 177 patients aged 18-85 years with chronic neck pain. INTERVENTIONS: Patients were randomly allocated to five treatments over three weeks with acupuncture (56), massage (60), or "sham" laser acupuncture (61). MAIN OUTCOME MEASURES PRIMARY OUTCOME MEASURE: maximum pain related to motion (visual analogue scale) irrespective of direction of movement one week after treatment. SECONDARY OUTCOME MEASURES: range of motion (3D ultrasound real time motion analyser), pain related to movement in six directions (visual analogue scale), pressure pain threshold (pressure algometer), changes of spontaneous pain, motion related pain, global complaints (seven point scale), and quality of life (SF-36). Assessments were performed before, during, and one week and three months after treatment. Patients' beliefs in treatment were assessed. RESULTS: One week after five treatments the acupuncture group showed a significantly greater improvement in motion related pain compared with massage (difference 24.22 (95% confidence interval 16.5 to 31.9), P=0.0052) but not compared with sham laser (17.28 (10.0 to 24.6), P=0.327). Differences between acupuncture and massage or sham laser were greater in the subgroup who had had pain for longer than five years (n=75) and in patients with myofascial pain syndrome (n=129). The acupuncture group had the best results in most secondary outcome measures. There were no differences in patients' beliefs in treatment. CONCLUSIONS: Acupuncture is an effective short term treatment for patients with chronic neck pain, but there is only limited evidence for long term effects after five treatments.

Acupuncture Analgesia↗
PubMedDate not supplied

[Randomised trial of acupuncture compared with conventional massage and "sham" laser acupuncture for treatment of chronic neck pain - range of motion analysis].

AIM: The aim of this study was to compare the effects of acupuncture on active motion of the cervical spine in patients with chronic neck pain with those of "sham" laser acupuncture and massage. MATERIAL AND METHODS: 177 patients with chronic neck pain were included in this prospective, randomized, placebo-controlled study. The patients were allocated by external randomization to five treatments over three weeks with acupuncture, massage and "sham" laser acupuncture. The range of active motion was measured by means of a 3D ultrasound real time motion analyzer. RESULTS: The analysis of cervical motion in three directions showed the largest increase in range of motion 14 days after acupuncture. Compared to massage, a significant improvement in total range of motion was seen in those patients treated by acupuncture immediately (p = 0,03) and one week (p = 0,03) weeks after therapy. There was no significant difference in those patients treated by sham laser acupuncture. CONCLUSION: The results of the study indicate that acupuncture is superior to conventional massage for improving active range of motion in patients with chronic neck pain. Because of its positive effects, its acceptance among patients and the lack of severe side effects, acupuncture can be recommended for the treatment of chronic neck pain, although there was no significant difference in results between "sham" laser acupuncture and acupuncture.

Acupuncture Therapy↗