Mobile Phone Headache: A Double Blind, Sham-Controlled Provocation Study

The objective was to test whether exposure to radio frequency (RF) fields from mobile phones may cause head pain or discomfort and whether it may influence physiological variables in individuals attributing symptoms to mobile phones, but not to electromagnetic fields in general. Seventeen eligible individuals, who experienced these symptoms in an open provocation test, took part in a double-blind, randomized provocation study with cross-over design. Sixty-five pairs of sham and mobile phone RF exposures were conducted. The increase in pain or discomfort (visual analogue scales) in RF sessions was 10.1 and in sham sessions 12.6 ( P = 0.30). Changes in heart rate or blood pressure were not related to the type of exposure ( P: 0.30-0.88). The study gave no evidence that RF fields from mobile phones may cause head pain or discomfort or influence physiological variables. The most likely reason for the symptoms is a nocebo effect.

The Erlangen Dose Optimization Trial for radiotherapy of benign painful shoulder syndrome. Long-term results

BACKGROUND AND PURPOSE

To evaluate the long-term efficacy of pain reduction by two dose-fractionation schedules for radiotherapy of painful shoulder syndrome.

PATIENTS AND METHODS

Between February 2006 and February 2010, 312 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS).

RESULTS

Median follow-up was 35 months (range 11-57). The overall early, delayed and long-term response rates for all patients were 83, 85 and 82 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 56.8 ± 23.7 and 53.2 ± 21.8 (p = 0.16); 38.2 ± 36.1 and 34.0 ± 24.5 (p = 0.19); 33.0 ± 27.2 and 23.7 ± 22.7 (p = 0.04) and 27.9 ± 25.8 and 32.1 ± 26.9 (p = 0.25), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 9.7 ± 3.0 and 9.5 ± 2.7 (p = 0.31); 6.1 ± 3.6 and 5.4 ± 3.6 (p = 0.10); 5.3 ± 3.7 and 4.1 ± 3.7 (p = 0.05) and 4.0 ± 3.9 and 5.3 ± 4.4 (p = 0.05), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28).

CONCLUSION

Radiotherapy is an effective treatment for the management of benign painful shoulder syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy.

Management of painful bone metastases: our experience according to scientific evidence on palliative radiotherapy

AIM

Our aim was to evaluate retrospectively the role of the radiotherapy in the multi-disciplinary management of pain due to bone metastases.

PATIENTS AND METHODS

A total of 305 patients received radiotherapy with or without bisphosphonate and antalgic drugs. Tolerability and efficacy were evaluated using a Numerical Rating Scale, Pain Intensity Difference evaluation scale related to administration of the drug, a 5-point verbal scale of the patients' general impression.

RESULTS

We found differences in some patient subgroups: pain reduction was significantly more evident in patients treated with a single-fraction radiotherapy scheme. Overall, 68% of patients experienced an improvement in pain control using concomitant drugs during radiotherapy.

CONCLUSION

Our study underlines the role of radiotherapy in the management of metastatic bone pain. The use of rapid-onset opioids to prevent predictable pain is a crucial step in managing radiotherapy. An interdisciplinary approach is recommended.

The Erlangen Dose Optimization trial for low-dose radiotherapy of benign painful elbow syndrome. Long-term results

BACKGROUND AND PURPOSE

To evaluate the long-term efficacy of pain reduction by two dose fractionation schedules used for low-dose radiotherapy of painful elbow syndrome.

PATIENTS AND METHODS

Between February 2006 and February 2010, 199 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS).

RESULTS

Median follow-up was 35 months (range 9-57 months). The overall early, delayed and long-term response rates for all patients were 80, 90 and 94 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 59.6 ± 20.2 and 55.7 ± 18.0 (p = 0.46); 32.1 ± 24.5 and 34.4 ± 22.5 (p = 0.26); 27.0 ± 27.7 and 23.5 ± 21.6 (p = 0.82) and 10.7 ± 15.0 and 21.5 ± 26.9 (p = 0.12), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 8.7 ± 2.9 and 8.1 ± 3.1 (p = 0.21); 4.5 ± 3.2 and 5.0 ± 3.4 (p = 0.51); 3.9 ± 3.6 and 2.8 ± 2.8 (p = 0.19) and 1.5 ± 2.3 and 2.4 ± 3.5 (p = 0.27), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28).

CONCLUSION

Low-dose radiotherapy is an effective treatment for the management of benign painful elbow syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy.

Local gene expression changes after UV-irradiation of human skin

UV-irradiation is a well-known translational pain model inducing local inflammation and primary hyperalgesia. The mediators and receptor proteins specifically contributing to mechanical or heat hyperalgesia are still unclear. Therefore, we irradiated buttock skin of humans (n = 16) with 5-fold MED of UV-C and assessed the time course of hyperalgesia and axon reflex erythema. In parallel, we took skin biopsies at 3, 6 and 24 h after UVC irradiation and assessed gene expression levels (RT-PCR ) of neurotrophins (e.g. NGF, BDNF, GDNF), ion channels (e.g. NaV1.7, TRPV1), inflammatory mediators (e.g. CCL-2, CCL-3) and enzymes (e.g. PGES, COX2). Hyperalgesia to mechanical impact (12 m/s) and heat (48°C) stimuli was significant at 6 h (p<0.05 and p<0.01) and 24 h (p<0.005 and p<0.01) after irradiation. Axon reflex erythema upon mechanical and thermal stimuli was significantly increased 3 h after irradiation and particularly strong at 6 h. A significant modulation of 9 genes was found post UV-C irradiation, including NGF (3, 6, 24 h), TrkA (6, 24 h), artemin, bradykinin-1 receptor, COX-2, CCL-2 and CCL-3 (3 and 6 h each). A significant down-regulation was observed for TRPV1 and iNOS (6, 24 h). Individual one-to-one correlation analysis of hyperalgesia and gene expression revealed that changes of Nav1.7 (SCN9A) mRNA levels at 6 and 24 h correlated to the intensity of mechanical hyperalgesia recorded at 24 h post UV-irradiation (Pearson r: 0.57, p<0.04 and r: 0.82, p<0.001). Expression of COX-2 and mPGES at 6 h correlated to the intensity of heat-induced erythema 24 h post UV (r: 0.57, p<0.05 for COX-2 and r: 0.83, p<0.001 for PGES). The individual correlation analyses of functional readouts (erythema and pain response) with local expression changes provided evidence for a potential role of Nav1.7 in mechanical hyperalgesia.

Radiation therapy for early stages of morbus Ledderhose

PURPOSE

To evaluate the efficacy of radiation therapy (RT) in the treatment of early stages of benign plantar fibromatosis (Morbus Ledderhose [ML]).

PATIENTS AND METHODS

From 2003 to 2008, 24 patients (33 sites) with a mean age of 52 years received RT for symptomatic ML. Prior to RT, 19 patients complained of pain and 15 had walking difficulties. 21 patients (28 sites) were irradiated with orthovoltage X-rays and three (five sites) received electron-beam irradiation. The RT protocol consisted of five weekly fractions of 3.0 Gy (15 Gy), repeated after 6 weeks to a total dose of 30 Gy in 20 patients (28 sites). In four patients (five sites), two single fractions of 4.0 Gy were applied, repeated at intervals of 4 weeks to total doses of 24-32 Gy. Primary study endpoints were the prevention of disease progression and the avoidance of a surgical intervention. Secondary endpoints were pain relief, improvement of gait, and patients' subjective satisfaction measured with a linear analog scale (LAS).

RESULTS

After a median follow-up of 22.5 months, none of the patients experienced a progression of number and size of the lesions or the clinical symptoms. In eleven sites (33.3%) complete remission of cords or nodules occurred, in 18 (54.5%) a reduced number or size was noted, and four sites (12.1%) were unchanged. Pain relief was achieved in 13/19 patients (68.4%), and an improvement of gait abnormalities was noted in 11/15 patients (73.3%). The patients' subjective satisfaction measured by means of the LAS revealed a median improvement of 3.5 points in 22/24 patients (91.6%). Skin or soft tissues toxicities RTOG grade > 2 were not noted.

CONCLUSION

RT is effective for treatment of the early stages of ML and may obviate the need for a surgical intervention. Long-term follow-up studies including a larger number of patients are required to define the role of RT in the management of this disorder.

Optimization of static magnetic field parameters improves analgesic effect in mice

The present study deals with the analgesic effect induced by static magnetic fields (SMF) in mice exposed to the field with their whole body. It discusses how the effect depends on the distribution of the magnetic field, that is, on the specification and arrangement of the applied individual permanent magnets. A critical analysis of different magnet arrangements is given. As a result the authors propose a magnet arrangement recipe that achieves an analgesic effect of over 80% in the writhing test. This is a widely accepted screening method for animal pain and predictor of human experimental results. As a non-drug, non-invasive, non-contact, non-pain, non-addictive method for analgesia with immediate and long-lasting effect based on the stimulus of the endogenous opioid network, the SMF treatment may attract the attention of medical doctors, nurses, magnet therapists, veterinarians, physiotherapists, masseurs, and fitness trainers among others.

Radiation therapy for painful heel spurs: results of a prospective randomized study

PURPOSE

To evaluate the efficacy of two different dose-fractionation schedules for radiation therapy (RT) in patients with painful heel spurs.

PATIENTS AND METHODS

130 patients were randomized into two groups: the low-dose (LD) group (n = 65 heels) received a total dose of 3.0 Gy given in two weekly fractions of 0.5 Gy; in the high-dose (HD) group (n = 65 heels), two weekly fractions of 1.0 Gy were applied over 3 weeks (total dose 6.0 Gy). In 24 sites of the HD group and 17 sites of the LD group, a second RT course was given. The results were assessed using a five-level function score which was documented before RT, at the end of each RT course, and at 6 weeks and 6 months thereafter.

RESULTS

At 6-month follow-up, RT led to a highly significant reduction of symptoms in both groups. In the HD group, 31 sites were classified as excellent (score: 90-100), 13 as good (score: 70-85), twelve as moderate (score: 45-65), and nine as poor (score: 0-40). In the LD group, 35 sites were classified as excellent, eight as good, ten as moderate, and twelve as poor. The comparison of the difference of the sum score and the single criteria before RT and at 6 months after RT using the Wilcoxon-Mann-Whitney U-test revealed no statistically significant difference of response to RT between both groups.

CONCLUSION

RT is an effective treatment option for the management of inflammatory heel spurs. The dose for an RT course should not exceed 3.0 Gy.

Low intensity permanent magnets in the treatment of chronic lumbar radicular pain

We assessed the pain-relieving efficacy of static magnetic fields produced by 200 Gauss (G) magnets compared with 50G magnets in a double-blind, randomized, two-phase crossover study in patients with chronic lumbar radicular pain. The surface field strengths of the magnets were 200 and 50G. Phase I included four random periods of two-week duration: two periods with 200G, one period with 50G, and one period of "no treatment." The magnets were positioned either vertically or horizontally in standard lumbosacral elastic corsets. Phase II consisted of two five-week periods with the most effective magnet from Phase I and its corresponding 50 or 200G device. The primary outcome was average daily leg pain score (0-10 scale) in each period of Phase II. Thirty-eight of 40 randomized patients completed Phase I, and 28 of 31 Phase II participants completed the study. In Phase I, pain scores did not differ significantly between 200 and 50G magnets. Phase II average leg pain scores tended to be lower with 200 vs. 50G magnets (3.2+/-2.1 for 200G vs. 3.9+/-2.2 for 50G magnets [P=0.08]) after excluding one unblinded patient. The relative treatment effect of the 200G magnets appeared to increase throughout the five-week period. Although these data cannot rule out a chance effect, the positive trends suggest that larger, longer-duration, sham-controlled trials with 200G magnets be considered in patients with chronic lumbar radicular pain.

Rhenium-186 Hydroxyethylidenediphosphonate (186Re HEDP) for the Treatment of Hemophilic Arthropathy

OBJECTIVES

The aim of this study was to evaluate the efficacy of a systemic application of rhenium-186 hydroxyethylidenediphosphonate (Re HEDP) for pain treatment in patients with hemophilic arthropathies.

METHODS

Twelve patients with hemophilic arthropathy with at least 3 involved joints with persistent pain were included in this prospective study. A single dose of 15 mCi (555 MBq) Re HEDP was administered intravenously. Before and 12 weeks after treatment, pain assessment was performed using the visual analog scale (VAS). The pain status assessment included the general status, pain of all joints affected, and pain of the 3 mostly involved joints. Furthermore, quality of life was assessed.

RESULTS

With regard to the 3 most involved joints, an improvement of the pain symptoms in 25 of 36 (69.4%) joints was observed. With regard to all involved joints a median of 3 joints per patient improved after Re HEDP therapy. General pain status after treatment was 2.0 VAS points lower as compared with pretreatment. The total number of involved joints remained unchanged in 7 patients, increased in 1 patient, and decreased in the remaining 4 patients.

CONCLUSIONS

The results of this study show an improvement of the pain symptoms of the involved joints 12 weeks after therapy with Re HEDP in patients with hemophilic arthropathy. The only moderate success regarding a reduction of the total number of involved joints is by the fact that despite this improvement most affected joints remained still painful on a lower level after the therapy or due to newly affected joints not painful before initiation of the radionuclide therapy.

INFLUENCE OF NERVE RADIATION DOSE IN THE INCIDENCE OF TRIGEMINAL DYSFUNCTION AFTER TRIGEMINAL NEURALGIA RADIOSURGERY

OBJECTIVE

The authors conducted a comparative study to analyze dosimetry and results to understand the significant difference in the rate of trigeminal dysfunction after gamma knife radiosurgery for trigeminal neuralgia between two centers using the same target.

METHODS

The data of 358 patients (109 patients from Brussels and 259 patients from Marseilles) were analyzed. Three different dosimetric strategies were found: treatment with less than 90 Gy and no selective beam channel blocking (Group 1; patients from Marseilles only), treatment with 90 Gy and no selective beam channel blocking (Group 2; patients from Brussels and Marseilles), or treatment with 90 Gy and use of selective beam channel blocking (Group 3; patients from Brussels only).

RESULTS

The prescription dose and the use of selective beam channel blocking have been significantly associated with a higher energy received by the retrogasserian trigeminal nerve root. The different radiation dose delivered to the nerve root in these three groups of patients was significantly associated with the incidence of mild (15, 21, and 49% for Groups 1, 2, and 3, respectively) and bothersome (1.4, 2.4, and 10% for Groups 1, 2, and 3, respectively) trigeminal dysfunction. The good and excellent rates of pain relief were 81 and 66%, respectively, for Group 1, 85 and 77%, respectively, for Group 2, and 90 and 84%, respectively, for Group 3, and were also related to the amount of energy received by nerve root volume.

CONCLUSION

Using a similar target, the incidence of trigeminal dysfunction and the pain relief rate can vary according to the radiation energy received by the retrogasserian part of the trigeminal nerve root. The prescription dose and the use of beam channel blocking modify the integrated dose delivered to the nerve and may contribute to the different rates of trigeminal numbness and pain outcome. The radiobiological effect of gamma knife radiosurgery may be related to the energy delivered to nerve root volume, rather than to the maximal dose delivered.

Influence of static magnetic fields on pain perception and sympathetic nerve activity in humans

Static and pulsed magnetic fields have been reported to have a variety of physiological effects. However, the effect of static magnetic fields on pain perception and sympathetic function is equivocal. To address this question, we measured pain perception during reproducible noxious stimuli during acute exposure to static magnets. Pain perception, muscle sympathetic nerve activity, mean arterial pressure, heart rate, and forearm blood velocity were measured during rest, isometric handgrip, postexercise muscle ischemia, and cold pressor test during magnet and placebo exposure in 15 subjects (25 ± 1 yr; 8 men and 7 women) following 1 h of exposure. During magnet exposure, subjects were placed on a mattress with 95 evenly spaced 0.06-T magnets imbedded in it. During placebo exposure, subjects were placed on an identical mattress without magnets. The order of the two exposure conditions was randomized. At rest, no significant differences were noted in muscle sympathetic nerve activity (8 ± 1 and 7 ± 1 bursts/min for magnet and placebo, respectively), mean arterial pressure (91 ± 3 and 93 ± 3 mmHg), heart rate (63 ± 2 and 62 ± 2 beats/min), and forearm blood velocity (3.0 ± 0.3 and 2.6 ± 0.3 cm/s). Magnets did not alter pain perception during the three stimuli. During all interventions, no significant differences between exposure conditions were found in muscle sympathetic nerve activity and hemodynamic measurements. These results indicate that acute exposure to static magnetic fields does not alter pain perception, sympathetic function, and hemodynamics at rest or during noxious stimuli.

Intradiscal high-voltage, long-duration pulsed radiofrequency for discogenic pain: a preliminary report

BACKGROUND

Intradiscal radiofrequency, with the electrode placed in the center of the nucleus pulposus, has been a controversial procedure in patients with discogenic pain. Possibly the effect has not been due to the production of heat, but to exposure to electric fields.

DESIGN

We have investigated the effect of high-voltage, long-duration intradiscal pulsed radiofrequency in patients with one-level discogenic low back pain, as confirmed by discography.

OUTCOME MEASURE

The pain intensity score on a 0-10 numeric rating scale (NRS) was taken as outcome measure.

PATIENTS

Eight patients were reported. The mean duration of pain was 6.3 years (range 0.5-16, median 4). The mean NRS score was 7.75 (range 5-9). Disc height was reduced 60% in one patient and up to 30% in the others.

INTERVENTION

A 15-cm, 20-gauge needle with a 15-mm active tip was placed centrally in the disc. Pulsed radiofrequency was applied for 20 min at a setting of 2 x 20 ms/s and 60 V.

RESULTS

There was a very significant fall in the NRS scores over the first 3 months (P < 0.0001). On an individual basis, all patients had a fall of the NRS score of at least 4 points at the 3-month follow-up. A follow-up of 12.8 months (range 6-25, median 9) was available for five patients. All these patients are now pain free, except for one patient with an NRS score of 2. Conclusion. It is concluded that this method merits a controlled, prospective study.

Pulsed radiofrequency denervation for the treatment of sacroiliac joint syndrome

OBJECTIVE

Current therapies for sacroiliac joint (SIJ) dysfunction offer discouraging results in alleviating low back pain. The innervation and target nerves for radiofrequency denervation (RFD) of the SIJ remain unclear. We present a prospective case series on the treatment of intractable SIJ dysfunction with pulsed radiofrequency denervation (PRFD) of lateral branches from L4-S3.

INTERVENTIONS

A total of 126 patients with presumptive SIJ dysfunction based on history and physical examination underwent arthrographically confirmed steroid/local anesthetic SIJ injection. Fifty-two patients (41.3%) had >75% pain relief after two consecutive injections, physical therapy, repeated SIJ injections, and/or analgesics. Twenty-two patients failed to respond. These patients underwent PRFD of the medial branch of L4, posterior primary rami of L5, and lateral branches S1 and S2.

OUTCOME MEASURES

Visual analog score (VAS) and quality of life (QOL) assessments were performed prior to and after treatment.

RESULTS

Sixteen patients (72.7%) experienced "Good" (>50% reduction in VAS), or "Excellent" (>80% reduction in VAS) pain relief following PRFD. Duration of pain relief range was 6-9 weeks in four patients, 10-16 weeks in five patients, and 17-32 weeks in seven patients. In addition, QOL scores improved significantly in all measured categories. Six patients (26.1%) did not respond to PRFD and had less than 50% reduction in VAS and were considered failures.

CONCLUSIONS

PRFD of the lateral branch of the medial branch of L4, posterior primary rami of L5, and lateral branches S1 and S2 is an effective treatment for some patients with SIJ pain unresponsive to other forms of therapy.

[186Re]HEDP in the palliation of painful bone metastases from cancers other than prostate and breast

AIM

Palliative therapy using [186Re]hydroxyethylidene diphosphonate (HEDP) has been widely tested in patients with bone metastases from prostate and breast cancers. Whereas, to the best of our knowledge, only few cases of bone metastases from tumors other than prostate and breast treated with [186Re]HEDP have been reported. The aim of this paper is to report our experience with 186Re-HEDP in the palliation of painful bone metastases from tumors other than prostate and breast.

METHODS

In this study 41 patients (17 non-small cell lung cancer-NSCLC, 1 small cell lung cancer, 1 lung neuroendocrine tumor, 8 bladder cancer, 3 kidney cancer, 3 gastric cancer, 1 uterine carcinoma, 1 colon cancer, 1 rhinopharynx carcinoma, 1 medullary thyroid carcinoma, 1 ovarian cancer, 1 esophagus cancer, 2 carcinoma of unknown origin) are evaluated. All patients had lesions with increased [99mTc]MDP uptake and none had radiological findings of mainly osteolytic lesions. A total of 46 therapeutic cycles were performed using a [186Re]HEDP activity of 1 295 MBq for each administration. After treatment, patients were followed up for 3 months or to the time of pain recurrence (if longer than 3 months). Responses were evaluated using a validated method considering the modifications of pain index, analgesic intake and performance status.

RESULTS

Treatment efficacy was complete in 49% (20/41) of patients, partial in 36% (15/41) and negative in 15% (6/41). Namely, we observed 35% (6/17) complete, 41% (7/17) partial and 24% (4/17) negative responses in patients with NSCLC and 63% (5/8) complete, 25% (2/8) partial and 12% (1/8) negative responses in patients affected by bladder cancer. The median duration of pain relief in responder patients was 10 weeks. A mild platelet toxicity occurred in 32% (13/41) of patients.

CONCLUSIONS

Pain palliation with [186Re]HEDP seems highly effective and safe also in patients with bone metastases from cancers other than prostate and breast. Patients who can benefit from the treatment with [186Re]HEDP can be selected on the basis of [99mTc]MDP bone scan and radiological examination findings.

Differential activation of trigeminal C or Adelta nociceptors by infrared diode laser in rats: behavioral evidence

Radiant heat is often used for studying thermal nociception, although inherent characteristics such as the broad spectrum of applied wavelengths of typical light sources limit control over and repeatability of stimuli. To overcome these problems, we used a diode infrared laser-based stimulator (wavelength: 980 nm) for selectively stimulating trigeminal Adelta or C thermonociceptors in rats. To provide indirect evidence for nociceptor-selective stimulation, we tested the effects of capsaicin, dimethylsulfoxide (DMSO), and morphine on withdrawal latencies for long pulses with a low current (hypothesized to selectively stimulate C nociceptors) and for threshold currents of short pulses with high current (hypothesized to selectively stimulate Adelta nociceptors) in lightly anesthetized rats. Nonmem analysis was used to perform pharmacodynamic modeling. The measured baseline withdrawal latency for long pulses was 12.5 +/- 0.3 s which was changed significantly to 6.7 +/- 0.4 s after applying topical capsaicin which selectively sensitizes C nociceptors and to 16.5 +/- 1.3 s after 1.0 mg/kg morphine which preferentially attenuates C fiber nociception. Topical DMSO which appears to selectively sensitize Adelta afferents did not significantly alter withdrawal latencies to the long pulses. Fitted threshold currents for short pulses after DMSO were however significantly lower (974 +/- 53 mA vs. 1113 +/- 12 mA for baseline) indicating Adelta sensitization. Capsaicin and morphine did not significantly change threshold currents. Best Nonmem fits for the long pulse were obtained using a model assuming no DMSO effect, but a different inter-individual variability after applying this substance. For the short pulse, a model assuming no capsaicin or morphine effect, but again allowing different inter-individual variabilities after applying these drugs, best described the data. We conclude that different settings of the stimulator used in this study were capable of selectively activating trigeminal Adelta or C thermonociceptors.

Activation of p38 MAPK in primary afferent neurons by noxious stimulation and its involvement in the development of thermal hyperalgesia

Alterations in the intracellular signal transduction pathway in primary afferents may contribute to pain hypersensitivity. We demonstrated that very rapid phosphorylation of p38 mitogen-activated protein kinase occurred in dorsal root ganglion (DRG) neurons that were participating in the transmission of noxious signals. Capsaicin injection induced phosphorylated-p38 (p-p38) in small-to-medium diameter sensory neurons with a peak at 2 min after capsaicin injection. Furthermore, we examined the p-p38 labeling in the DRG after noxious thermal stimuli and found a stimulus intensity-dependent increase in labeled cell size and the number of activated neurons. Most of these p-p38-immunoreactive (IR) neurons were small- and medium-sized neurons, which coexpressed transient receptor potential ion channel TRPV1 and phosphorylated-extracellular signal-regulated protein kinase. Intrathecal administration of the p38 inhibitor, FR167653, reversed the thermal hyperalgesia produced by the capsaicin injection. Inhibition of p38 activation was confirmed by the decrease in the number of p-p38-IR neurons in the DRG following capsaicin injection. Taken together, these findings suggest that the activation of p38 pathways in primary afferents by noxious stimulation in vivo may be, at least in part, correlated with functional activity, and further, involved in the development of thermal hyperalgesia.

Human exposure to a specific pulsed magnetic field: effects on thermal sensory and pain thresholds

Exposure to pulsed magnetic fields (MF) has been shown to have a therapeutic benefit in both animals (e.g. mice, snails) and humans. The current study investigated the potential analgesic benefit of MF exposure on sensory and pain thresholds following experimentally induced warm and hot sensations. Thirty-nine subjects (Study 1) and 31 subjects (Study 2) were randomly and double-blindly assigned to 30 min of MF or sham exposure between two sets of tests of sensory and pain thresholds and latencies at, 1 degrees C above, and 2 degrees C above pain thresholds. Results indicated that MF exposure does not affect sensory thresholds [e.g. [F(1,31) = 0.073, NS]. Pain thresholds were significantly increased following MF exposure [F(1,6) = 9.45, P < 0.01] but not following sham exposure [F (1,4) = 4.22, NS]. A significant condition by gender interaction existed for post-exposure pain thresholds [F(1,27) = 5.188, P < 0.05]. Taken together, these results indicate that MF exposure does not affect basic human perception, but can increase pain thresholds in a manner indicative of an analgesic response. The potential involvement of the placebo effect is discussed.

Effects of magnetic field exposure on open field behaviour and nociceptive responses in mice

Results of previous studies have shown that nociceptive sensitivity in male C57 mice is enhanced by exposure to a regular 37 Hz or an irregularly varying (<1 Hz) electromagnetic field. In order to test whether these fields affect more generally mouse behaviour, we placed Swiss CD-1 mice in a novel environment (open field test) and exposed them for 2 h to these two different magnetic field conditions. Hence, we analysed how duration and time course of various behavioural patterns (i.e. exploration, rear, edge chew, self-groom, sit, walk and sleep) and nociceptive sensitivity had been affected by such exposure. Nociceptive sensitivity was significantly greater in magnetically treated mice than in controls. The overall time spent in exploratory activities was significantly shorter in both magnetically treated groups (< 1 Hz, 33% and 37 Hz, 29% of total time), than in controls (42%). Conversely, the time spent in sleeping was markedly longer in the treated groups (both 27% of total time) than in controls (11%). These results suggest that exposure to altered magnetic fields induce a more rapid habituation to a novel environment.

Exposure to a hypogeomagnetic field or to oscillating magnetic fields similarly reduce stress-induced analgesia in C57 male mice

Previous studies have shown that exposure to altered magnetic fields alters analgesic responses in a variety of species, including humans. Here we examined whether deprivation of the normally occurring geomagnetic field also affects stress-induced analgesia, by measuring the nociceptive responses of C57 male mice that were restraint-stressed in a hypogeomagnetic environment (inside a mu-metal box). Stress-induced analgesia was significantly suppressed in a manner comparable to that observed in mice that were either exposed to altered oscillating magnetic fields or treated with the prototypic opiate antagonist naloxone. These results represent the first piece of evidence that a period in a hypogeomagnetic environment inhibits stress-induced analgesia.

[Intraoperative radiation therapy (IORT) for locally unresectable pancreatic cancer]

To evaluate the therapeutic effect of IORT for unresectable locally advanced pancreatic cancer, 11 patients treated with IORT and 15 patients treated with palliative therapy only were retrospectively examined. The mean age of the IORT group was 61.9 years, 5 cases were classified into surgical stage IVa, and 6 into stage IVb. The mean age of the palliative therapy group was 69.1 years; 5 cases were classified into surgical stage IVa and 10 into stage IVb. The tumor size was measured in 6 cases in the IORT group, before and after IORT. The tumor was enlarged in 1 case, not changed in 4 cases, and reduced in 1 case. The serum CA19-9 level was measured in 8 cases of the IORT group. Serum CA19-9 was increased in 3 cases, not changed in 4 cases, and decreased in 1 case after IORT. ECOG pain scores were obtained in 9 patients who had complained of pain before IORT, and the score decreased in 7 cases. The median survival was 7.6 months in the IORT group and 3.0 months in the palliative therapy group. IORT may improve patients' QOL by decreasing their pain. However, further studies are necessary to confirm the efficacy of IORT for survival of locally unresectable pancreatic cancer patients, because the patient profile in this study was different in the two groups.

Analgesic effects of cranial laser treatment in two rat nociception models

The present experiments sought to establish dose dependency and time course for effects of cranial laser irradiation in two rodent models of pain. These were the hot plate and tail flick tests, which are both widely used to quantify analgesic drug effects. The laser used was an Omega Biotherapy 3ML (wavelength 820 nM, average power output 100 mW, pulse frequency 5 kHz) and irradiation was applied to rats' shaved heads above the midbrain. In the first experiment, four groups of 10 rats received doses of 0, 6, 12, 18, and 24 J/cm2 in random orders prior to hot plate testing either immediately, 30 min, 1 h or 24 h postlaser. The second study employed three groups of 10 rats receiving 0, 12, and 18 J/cm2 in random orders prior to tail flick testing at the three shorter times above. Latency to lick hind paws on the hot plate was highly significantly prolonged by laser treatment across all doses and time periods, F(4, 126) = 4.51, p < 0.01. There was good dose dependency for immediate observations, but at 24 h 18 J/cm2 was the most effective dose. Laser treatment also delayed tail flick responses at both doses and all time periods, F(2, 54) = 10.60, p < 0.001, but 12 and 18 J/cm2 doses were similar in efficacy.

[Radiotherapy for symptomatic osseous metastases: special reference to the analysis of patients achieved complete pain relief]

A total of 223 patients with 498 symptomatic osseous metastases treated by radiotherapy between July 1985 and June 1991 were retrospectively analyzed. Most sites, 409 (82%), were irradiated by conventional fractionation, while the remaining 89 sites were irradiated by dose-increment fractionation, low-dose short schedules or hyperfractionation. The total dose ranged from 5.4 to 74 Gy (mean, 41.4 Gy). Daily pain assessment was done by patients themselves on an 11-point scale, i.e., 10: pretreatment pain, 0: disappearance of pain following radiotherapy. In addition, improvement in performance status (PS) and the duration of complete pain relief were assessed. The following results were obtained. 1) Pain relief: Of 498 evaluated sites, complete pain relief and partial pain relief were achieved in 403 sites (81%) and 64 sites (13%), respectively. No significant difference was seen in the incidence of complete pain relief between weight-bearing bone and non-weight-bearing bone. Patients with PS 1, 2 or 3 were significantly superior to those with PS 4 in terms of complete pain relief (P < 0.05-0.001). The complete response rate increased in accordance with the dose delivered, i.e., 49% at 20 Gy, 70% at 30 Gy and 77% at 40 Gy, in all of the 498 sites irradiated; 60%, 86% and 95% of 403 sites, respectively, achieved complete pain relief. Regarding the fractionation regimens, dose-increment fractionation was superior to both conventional fractionation and low-dose short schedules in terms of complete pain relief rate. 2) Improvement of PS: Of 223 evaluated patients, PS was improved 1 to 3 steps in 162 (73%) at the completion of radiotherapy. The improvement rates of patients with PS 2 or 3 were significantly better than those with PS 4 (P < 0.025, 0.001). 3) Duration of complete pain relief: Of 288 appraisable sites, the recurrence of pain was recognized in 23 (9%) at intervals of 3 to 21 months (median, 5 months). On the other hand, the duration of pain relief was 16 to 79 months (median, 32 months) in 26 sites of survivors, and 1 to 28 months (median, 5 months) in 239 sites of decreased patients. The mean total dose was 48.5 Gy (TDF: 82) to 62 sites with a duration of pain relief of more than 13 months. 4) Re-irradiation to the same site: Of 14 sites retreated after initial complete response with a total dose of 30 to 50 Gy (mean, 48 Gy), 11 (79%) were in weight-bearing bone and 9 (64%) responded completely. 5) Patients with unsatisfactory pain relief (pain score > or = 6): Of 31 sites, 27 (94%) were in patients with PS 4, and 19 (61%) received a total dose below 30 Gy. 6) The 11-point scale for patient self-assessment of pain relief following radiotherapy was thought to be useful and easy to adopt in general clinics.