ATP responses in human C nociceptors

Microelectrode recordings of impulse activity in nociceptive C fibres were performed in cutaneous fascicles of the peroneal nerve at the knee level in healthy human subjects. Mechano-heat responsive C units (CMH), mechano-insensitive but heat-responsive (CH) as well as mechano-insensitive and heat-insensitive C units (CM(i)H(i)) were identified. A subgroup of the mechano-insensitive units was readily activated by histamine. We studied the responsiveness of these nociceptor classes to injection of 20 microl 5 mM adenosintriphosphate (ATP) using saline injections as control. Because of mechanical distension during injection, which typically activates mechano-responsive C fibres, interest was focused on responsiveness to ATP after withdrawal of the injection needle. Post-injection responses were observed in 17/27 (63%) mechano-responsive units and in 14/22 (64%) mechano-insensitive units. Excitation by ATP occurred in 9/11 CH units and in 5/11 CM(i)H(i) units. ATP responsive units were found both within the histamine-responsive and the histamine-insensitive group of mechano-insensitive fibres. ATP responses appeared with a delay of 0-180 s after completion of injection; responses were most pronounced during the first 1-3 min of activation, and irregular ongoing activity was observed for up to 10 or even 20 min. ATP responses were dose-dependent, concentrations lower than 5 mM gave weaker responses. No heat or mechanical sensitisation was observed in any of the major fibre classes. In conclusion, we have shown that ATP injections at high concentrations activate C-nociceptors in healthy human skin, without preference for mechano-responsive or mechano-insensitive units. ATP did not sensitise human C fibres for mechanical or heat stimuli. We discuss how various mechanisms might contribute to the observed responses to ATP.

Sensitivity of the negative mucosal potential to the trigeminal target stimulus CO(2)

CO(2) is frequently used in an experimental pain model and in imaging studies investigating the central processing of trigeminal nociceptive information because of its specific trigeminal stimulation properties. The aim of the current study was (1) to investigate the sensitivity of the NMP to small increments of CO(2) stimulus concentrations (3% CO(2), v/v) and (2) to characterize the sensory input of CO(2) by determining NMP, detection and pain thresholds and by registering subjective verbal descriptions. Ten subjects participated in the first experimental sessions investigating NMP responses to stimuli of 62, 65, 68% CO(2) (v/v) (stimulus duration: 1000 ms). Our statistical analysis revealed a dose-dependent increase of the NMP amplitudes and areas under the curves (AUCs) demonstrating the high dynamic resolution of the NMP. Ten subjects participated in the second experimental sessions determining thresholds for NMP, detection and pain (stimulus duration: 1000 ms). MANOVA analysis revealed significantly different thresholds for detection, NMP and subjective pain judgements (mean and S.D. as percentage CO(2) (v/v): detection: 20.6+/-9.6, NMP: 42.6+/-12.5, pain: 50.4+/-12.0). We could demonstrate the existence of a prepain range below subjective pain thresholds with activation of trigeminal nociceptive sensors resulting in the generation of NMPs. The detection threshold of 20.6% CO(2) (v/v) was surprisingly low, i.e. 22% CO(2) (v/v) below the NMP threshold. The involvement of newly discovered alpha-gustducin positive trigeminal chemosensory cells in CO(2) detection is hypothesized.

Some effects of Salvia aegyptiaca L. on the central nervous system in mice

Salvia aegyptiaca L. is used for treating various unrelated conditions that include nervous disorders, dizziness, trembling, diarrhoea and piles. This work examines some effects of the crude acetone and methanol extracts of the plant given at single oral doses of 0.25, 0.5, 1 or 2 g/kg, on the central nervous system (CNS) in mice. The extracts were also tested for anti-inflammatory and antipyretic actions. Several models of nociception have been used to examine the analgesic effect of the extract. In treated mice, the extracts caused dose-related inhibition of acetic acid-induced abdominal constriction, and significantly reduced formalin-induced pain. Treatment with the extracts at doses of 0.5 and 1 g/kg significantly increased the reaction time in the hot-plate test. In treated mice both extracts caused significant and dose-related impairment of the sensorimotor control and motor activity. Treatment with both extracts did not significantly affect the rectal temperature of normothermic mice. The methanol extract (0.5 and 1.0 g/kg) did not affect the rectal temperature of hyperthermic mice, but the acetone extract was effective in significantly reducing the rectal temperature of hyperthermic mice, 0.5 and 1 h after administration of the extract at doses of 0.25-2 g/kg. It is concluded that the crude methanol and acetone extracts of S. aegyptiaca have CNS depressant properties, manifested as antinociception and sedation. Both extracts have some anti-inflammatory and antipyretic actions. On the whole, the acetone extract appeared to be slightly more effective than the methanol extract in this regard.

Synthesis, antiinflammatory and analgesic activity of new hexahydropyrimidine derivatives

A number of potentially active hexahydropyrimidine derivatives of pharmaceutical interest have been synthesized. Various diSchiff's bases prepared by reacting different aromatic aldehydes with 1,3-diaminopropane were suitably reduced to give their tetrahydro derivatives which were then condensed with appropriate aldehydes to give a series of hitherto unreported hexahydropyrimidines. The resulting products were evaluated by oral route for their antiinflammatory activity. The activity of compounds 11, 23 and 4 was excellent and comparable to indomethacin. In addition to oral route of administration, the antiinflammatory activity of hexahydropyrimidine derivatives was also studied topically through transdermal gels. Compounds 11, 23, 4 and 22 produced significant inhibition in edema and showed good antiinflammatory activity comparable to diclofenac sodium gel (Relaxyl gel). All these compounds were also tested for their analgesic activity and their LD50 determined. Compounds 11, 20 and 23 showed a comparable activity with aspirin. The MTD for all the compounds was found to be > 1800 mg/kg.

Evaluation of the antinflammatory and analgesic activity of Sideritis canariensis var. pannosa in mice

A previous chemical study of Sideritis canariensis var. pannosa demonstrated the presence of some important classes of related organic compounds with anti-inflammatory activities. In the present study, the crude ethanol extract and the chloroformic and aqueous fractions of S. canariensis have been examined for their antimicrobial actions through the disk-diffusion method and for their anti-inflammatory and analgesic effects in several animal models. No relevant antimicrobial activity against the tested microorganisms was found. The chloroformic fraction was the most interesting, exhibiting a good analgesic and anti-inflammatory activity.

Efficacy of microfiltration in decreasing propofol-induced pain

In a randomised, double-blinded, two-centre trial we evaluated the effect of a microbiological filter (Supor, Pall Life Sciences) on propofol injection pain. We studied 336 unpremedicated adult patients, who graded pain experienced during induction of anaesthesia with propofol on a 4-point verbal rating scale. Use of the microfilter reduced both the incidence and severity of propofol injection pain (p < 0.001). Incidence of severe pain in the filter group was 2.4% compared with 16.6% in the control group. Overall, 33.7% in the filter group experienced pain compared with 62.1% in the control group. A microbiological filter may provide a non-pharmacological alternative to a lidocaine/propofol mixture for reducing injection pain. It would also reduce the risk of any glass and bacterial contamination.

Excruciating perineal pain after intravenous dexamethasone

We describe two cases of unexpected perineal pain immediately after intravenous injection of fentanyl and dexamethasone (100 microg and 8 mg respectively) during induction of general anaesthesia. In both cases the pain was immediate (onset within 30 seconds), severe, localized to the genital region and of shooting and burning character No other clinical signs or symptoms were observed in either case and both patients made an uneventful recovery without neurological sequelae. We review the existing literature on perineal pain as an adverse effect of intravenous corticosteroid esters and recommend their administration either in diluted form or after induction of general anaesthesia.

Capsazepine inhibits thermal hyperalgesia but not nociception triggered by protease-activated receptor-2 in rats

Protease-activated receptor-2 (PAR-2), expressed in sensory neurons, triggers thermal hyperalgesia, nociceptive behavior and spinal Fos expression in rats. In the present study, we examined if the nociceptive processing by PAR-2 is mediated by trans-activation of capsaicin receptors. The thermal hyperalgesia following an intraplantar (i.pl.) administration of the PAR-2-activating peptide SLIGRL-NH2 was completely abolished by the capsaicin receptor antagonist capsazepine. In contrast, neither the nociceptive behavior nor spinal Fos expression in response to i.pl. SLIGRL-NH2 were attenuated by capsazepine. Our data imply that trans-activation of capsaicin receptors by PAR-2 might be involved in the PAR-2-triggered thermal hyperalgesia, but not nociception.

[Adverse reactions after vaccination against influenza in chronically ill people]

The objective was to assess the early and late adverse reactions after vaccination against influenza with the help of SmithKline Beecham's Fluarix vaccine in chronically ill people. 1010 people was selected to undergo vaccination. These included 621 woman aged average 44.2 and 389 men aged average 48.2. The vaccination was conducted simultaneously and the period of monitoring adverse reactions lasted 9 months. The vaccination was done in accordance with recommendations of manufacturer. All the vaccinated people suffered from circulatory system disorders, bone system disorders, mental disorders and endocrinological problems, during the vaccination they were in period of remission. The observed early symptoms fell into two categories: local and general. The late adverse reaction assessed with appearance of aggravation of main chronic disease or with appearance of the new chronic disease. The local symptoms included swelling, reddening and pain in the vaccinated area. 67 people (6.6%) reported swelling, 85 (8.4%) reported reddening, 12 people (1.2%) reported pain in the vaccinated area. The general symptoms included headache, bad mood and temperature over 37.5 degrees C. 19 people (1.9%) reported bad mood, 10 people (1%)--headache and 8 people (0.8%) reported temperature over 37.5 degrees C. Coexistence of two or three types of symptoms was present in 15 cases (1.5%). There were no late adverse reactions in the study group. The low percentage of early adverse reactions and no late adverse reactions encourages a wider use of vaccines against influenza in chronically ill people.

Oral methotrexate for treatment of ectopic pregnancy

OBJECTIVE

The purpose of this study was to evaluate oral methotrexate tablets in the treatment of ectopic pregnancy.

STUDY DESIGN

Patients with a diagnosis of ectopic pregnancy were offered oral methotrexate tablets rather that intramuscular injection. Oral methotrexate was given in 2 divided doses 2 hours apart at a dose of 60 mg/m(2) with standard 2.5 mg methotrexate tablets. Patients were followed up with the use of the same protocol that was used typically for intramuscular methotrexate.

RESULTS

Nineteen of 22 patients (86%) were successfully treated. There was no statistical difference between patients who were treated successfully or unsuccessfully, with respect to initial human chorionic gonadotropin titers (P =.55), ectopic size (P =.77), or methotrexate dose (P =.18). Nineteen of 22 patients (86%) had increased pain during treatment. Outside of pain, gastrointestinal side effects were the most common. Thirty-two percent of patients required more than one treatment cycle.

CONCLUSION

Oral methotrexate can be used to treat ectopic pregnancy successfully, but there are few advantages to recommend its use over intramuscular methotrexate.

Pseudo-akuammigine, an alkaloid from Picralima nitida seeds, has anti-inflammatory and analgesic actions in rats

Pseudo-akuammigine, an alkaloid from Picralima nitida seed extract was investigated for anti-inflammatory and analgesic actions using the carrageenan-induced rat paw oedema and the rat tail flick. The alkaloid, at 1.0, 5.0 and 50 mgkg(-1)(,) dose-dependently inhibited the mean maximal paw swelling attained during 6 h to 78.2+/-2.1, 74.7+/-4.3 and 59.5+/-2.3% of the mean control value respectively when administered p.o. 1 h before induction of oedema. At the same dose levels, the total paw swelling over the 6-h period was also significantly (P<0.05) reduced to 83.2+/-9.7, 73.0+/-5.0 and 55.8+/-8.3% of the mean control response respectively. When administered after induction of oedema, psi-akuammigine (5.0 mgkg(-1)) significantly (P<0.05) reduced established rat paw swelling to 82.8+/-4.6% of the control response after 5 h. As an analgesic, psi-akuammigine was 3.5 and 1.6 times less potent than morphine and indomethacin respectively. The ED(50) values were Morphine (2.9 microM), psi-akuammigine (10 microM) and indomethacin (6.3 microM). Naloxone (1.0 mgkg(-1)) significantly (P<0.05) antagonised the analgesic action of the alkaloid by 35.8+/-6.8%. Pseudo-akuammigine therefore exhibits anti-inflammatory and analgesic actions. The analgesic actions are mediated via interaction with opioid receptors.

Effects of docetaxel on pain due to metastatic androgen-independent prostate cancer

Bone pain commonly plagues patients with metastatic androgen-independent prostate cancer. Studies of mitoxantrone demonstrated that chemotherapy can substantially reduce this debilitating symptom. Two of the available studies examining the use of docetaxel with and without estramustine for treatment of androgen-independent prostate cancer include a detailed prospective analysis of pain and quality of life. One study required patients to have pain at entry and demonstrated significant improvement in pain. The second study enrolled patients with low prevalence and intensity of pain and did not demonstrate pain relief. The available results, although preliminary, suggest that patients with significant bone pain due to androgen-independent prostate cancer can experience substantial pain relief with docetaxel-based therapy. Larger randomized studies targeting patients with sufficient prevalence and intensity of pain are needed to refine our understanding of the contribution of docetaxel to pain control in this patient population.

Dual effect of nitric oxide in articular inflammatory pain in zymosan-induced arthritis in rats

The contribution of nitric oxide (NO) to articular pain in arthritis induced by zymosan (1 mg, intra articular) in rats was assessed by measuring articular incapacitation (AI). Systemic treatment with the non-selective NO synthase (NOS) inhibitor L-NAME (10 - 100 mg kg(-1) i.p.) or with the selective iNOS inhibitors aminoguanidine (AG; 10 - 100 mg kg(-1) i.p.) or 1400W (0.5 - 1 mg kg(-1) s.c.) inhibited the AI induced by injection of zymosan 30 min later. Local (intra articular) treatment with the NOS inhibitors (L-NAME or AG, 0.1 - 1 micromol; 1400W, 0.01 (micromol) 30 min before zymosan also inhibited the AI. Systemic or local treatment with the NOS inhibitors (L-NAME; AG, 100 mg kg(-1) i.p. or 0.1 micromol joint(-1); 1400W, 1 mg kg(-1) s.c. or 0.01 micromol joint(-1)), 2 h after zymosan did not affect the subsequent AI. Local treatment with the NO donors SNP or SIN-1, 2 h after zymosan did inhibit AI. L-NAME and AG, given i.p. inhibited nitrite but not prostaglandin E(2) (PGE(2)) levels in the joints. L-NAME (100 mg kg(-1)) but not AG (100 mg kg(-1)) increased mean arterial blood pressure. Neither L-NAME, AG nor the NO donor SIN-1 altered articular oedema induced by zymosan. In conclusion, inhibitors of iNOS decrease pain in zymosan arthritis only when given before the zymosan. This was not due to inhibition of articular PGE(2) release or oedema. NO donors also promoted antinociception in zymosan arthritis without affecting oedema.

Anti-inflammatory and antinociceptive properties of dantrolene sodium in rats and mice

Our study aimed at examining the possible anti-inflammatory and antinociceptive effects of dantrolene sodium in rats and mice. The anti-inflammatory effect of dantrolene sodium (2.5, 5 and 10 mg kg (-1)) was investigated and compared with diclofenac sodium (5 mg kg (-1)) using the formalin-, histamine-, and carrageenan-induced paw oedema and cotton pellet granuloma tests. Analgesic effects of dantrolene sodium were evaluated and compared with metamizol (200 mg kg (-1)) in acetic acid-induced writhing and formalin-induced paw licking tests. It was found that dantrolene sodium significantly diminished the nociceptive response in mice, showing at the same time considerable anti-inflammatory properties in rats.

Do the epilepsies, pain syndromes, and affective disorders share common kindling-like mechanisms?

Kindling, in the classical sense, involves progressively increasing responsivity to the intermittent repetition of the same 1-s subthreshold electrical stimulation over time, with the amygdala being the area most frequently studied. Such repeated subthreshold stimulation is associated with: lowering of the after-discharge (AD) threshold; lengthening and spread of the AD; marked seizure stage progression culminating in full-blown tonic-clonic forelimb convulsions with rearing and falling; and evolution from triggered to spontaneous seizures. This evolving process concomitantly involves changes in the spatio-temporal expression of immediate early genes (IEGs), neurotrophic factors, and late effector genes (LEGs), and an associated changing pattern of effectiveness of different pharmacological interventions. Since seizures are the paradigmatic behavioral manifestation of kindling, some types of pharmacological seizures, such as those induced by the local anesthetics cocaine and lidocaine, and some epileptic syndromes, are most likely homologously modeled by kindling. However, since non-epileptiform syndromes, such as recurrent episodes of affective illness and some pain syndromes possess non-homogenous elements of kindling-like evolution, some of the principles involved in kindling progression may, nonetheless, be pertinent to the understanding and treatment of these syndromes. For example, one could attempt to distinguish between the genes involved in the primary pathological processes of syndrome evolution versus those that are secondary and adaptive; such a differentiation could have important implications for the development of therapeutic approaches targeted to suppressing or enhancing these alterations, respectively. In these instances, inferences drawn from the kindling model are necessarily indirect and circumscribed because different neuroanatomical and biochemical processes are likely involved in the evolution of each neuropsychiatric syndrome. Given these recognized limitations of non-homologous models, kindling may still provide insights into the longitudinal course, progression, and treatment of some neuropsychiatric syndromes that can then be directly tested in the clinic.

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.

Exposure to the estrogenic pollutant bisphenol A affects pain behavior induced by subcutaneous formalin injection in male and female rats

We investigated the effects of perinatally administered bisphenol A (BPA), an environmental contaminant with estrogenic activity, on formalin-induced nociceptive responses. Male and female offspring of mother rats treated with BPA or oil were cross-fostered after birth to obtain three homogeneous groups: BPA-prenatal, receiving BPA via the placenta; BPA-postnatal, receiving BPA through suckling; OIL, control, from mothers receiving only peanut oil (vehicle). All groups underwent a pain test with s.c. formalin injection (50 microl, 10%) or were sham injected (pricking with a syringe needle) in the dorsal hind paw. They were immediately placed in an open field apparatus where pain responses (licking, flexing and paw-jerk) were recorded for 60 min. Corticosterone, testosterone and estradiol serum levels were determined in blood obtained at the end of the experiment. BPA-prenatal treatment induced an increase in licking duration in females and in flexing duration in both sexes in the first half of the test (0-30 min after formalin injection). BPA-postnatal treatment induced a decrease in paw-jerk frequency in males and females during the second part of the test (30-60 min after formalin injection). Plasma concentrations of corticosterone, estradiol and testosterone did not differ significantly between groups. These results indicate that exposure to BPA modified the activity of neural pathways and/or centers involved in nociception and pain in a sex-related and exposure-related manner.

Effects of somatosensory cortical stimulation on expression of c-Fos in rat medullary dorsal horn in response to formalin-induced noxious stimulation

We examined the effects of epidural electrical stimulation of primary (SI) and secondary (SII) somatosensory cortex on expression of c-Fos protein in rat medullary dorsal horn neurons (Vc; trigeminal nucleus caudalis) in response to formalin-induced noxious stimulation. Epidural electrical stimulation (single pulse, 0.2 msec duration at 10 Hz) was applied to the left facial region SI or SII at three different stimulus intensities, 0.1, 0.5, and 1.0 mA for 60 min 0 or 2 hr after bilateral injection of formalin into the lower lip. SII stimulation at 1.0 mA immediately after injection of formalin, significantly decreased the number of Fos-positive cells in the right VcI/II by 32.4%. There was no significant change in the number of Fos-positive cells in the VcIII/IV. SII stimulation at 0.5 and 1.0 mA 2 hr after injection of formalin, significantly decreased the number of Fos-positive cells in the right VcI/II by 47.9% and 40.8%, but significantly increased the number of Fos-positive cells in the right VcIII/IV by 178.8% and 324.3%, respectively. In contrast, SI stimulation had no effect on expression of c-Fos in Vc. Possible direct corticotrigeminal projections were labeled anterogradely by injection of WGA-HRP into the SI and SII. In the Vc, labeled terminals were distributed mostly in the contralateral medial half of VcIII/IV and medullary reticular nucleus dorsalis but rarely in VcI/II. These results suggest that activation of SII-medullary fibers suppress nociceptive information from the oro-facial regions.

Experimental itch in sodium lauryl sulphate-inflamed and normal skin in humans: a randomized, double-blind, placebo-controlled study of histamine and other inducers of itch

BACKGROUND

Investigations of pruritogenic substances in humans have involved intradermal injections in normal skin; itching of inflamed skin has been little studied.

OBJECTIVES

To develop an itch model with provocation of itch in experimentally inflamed skin as well as in normal skin, using subjects as self-controls.

METHODS

In 32 non-atopic volunteers aged 21-30 years, the skin of five selected test sites on one volar forearm was pretreated for 24 h with large Finn chambers containing 1% sodium lauryl sulphate (SLS) used as a standard contact irritant to induce inflammation. Twenty microlitres of different pruritogenic substances [histamine, substance P, neurokinin A, neurokinin B, trypsin, platelet-activating factor (PAF) and serotonin] and saline as control were injected intradermally into the inflamed test sites and in corresponding non-treated sites on the opposite forearm. The test individuals scored itch intensity on a visual analogue scale for 20 min, and weal area was then measured. :

RESULTS

Histamine and substance P induced itch in both normal and inflamed skin compared with a saline reference. Neurokinin A, trypsin, PAF and serotonin only elicited itch in normal skin, and neurokinin B neither elicited itch in normal skin nor in inflamed skin. Itch was induced in normal and SLS-inflamed skin to a similar magnitude. However, weal area after histamine was significantly (P < 0.001) larger in inflamed skin when compared with normal skin.

CONCLUSIONS

Histamine and substance P elicited itch to the same degree in normal skin and inflamed skin pretreated with SLS despite a stronger weal response in inflamed skin. Mediators present in inflamed skin did not potentiate itch, a c-fibre-mediated neuronal response. The weal reaction is based on enhanced vascular permeability (protein extravasation). A greater skin perfusion in inflamed skin may therefore have increased the weal size. We propose an experimental model in humans for testing of itch involving both normal and inflamed skin. The model has the potential for use in evaluating new topical and systemic treatments of itch.

Comparison of abortions induced by methotrexate or mifepristone followed by misoprostol

OBJECTIVE

To compare the effectiveness, side effects, and acceptability of medical abortions induced by methotrexate and misoprostol with abortions induced by mifepristone and misoprostol.

METHODS

This was a multicenter, randomized, nonblinded, controlled trial comparing 50 mg/m(2) of methotrexate followed 4-6 days later by 800 microgram of vaginal misoprostol with 600 mg of oral mifepristone followed 36-48 hours by 400 microgram of oral misoprostol.

RESULTS

There were 518 women in the methotrexate group and 524 women in the mifepristone group. In the methotrexate group, 21 women required suction curretage, two for continuing pregnancy, eight because of physician request (usually for excessive bleeding), and 11 because of patient request. In the mifepristone group, 22 women needed surgical termination, 17 because of physician request, and five because of patient request. By day 8, only 386 (74.5%) in the methotrexate group had completed the abortion compared with 474 (90.5%) in the mifepristone group, and the mean number of days from beginning to completion was 7.1 for methotrexate and 3.3 for mifepristone (P </=.001). There were no differences in complications, and side effects were similar. Acceptance was slightly higher with mifepristone (88.0%) than with methotrexate (83.2%).

CONCLUSION

Abortions induced with mifepristone completed faster than those induced with methotrexate, but the overall success rates, side effects, and complications were similar. Acceptance rates were slightly higher with mifepristone than methotrexate (P =.03).

Immunohistochemical localization of endomorphin-1 and endomorphin-2 in immune cells and spinal cord in a model of inflammatory pain

Recently, two novel highly selective mu-opioid receptor (MOR) agonists, endomorphin-1 and endomorphin-2, have been isolated from bovine as well as human brains and were proposed to be the endogenous ligand for MOR. Later, endomorphin-1 and endomorphin-2 have been detected in the immune system of rats and humans using radioimmunoassay in combination with reverse-high-phase-liquid chromatography. In the present study, we analyzed the expression of endomorphin-1, endomorphin-2 and MOR by immunohistochemistry in a model of Freund's complete adjuvant (FCA)-induced painful inflammation. While MOR was upregulated on peripheral and central nerve terminals, inflammation did not alter endomorphin-2 expression in nerve fibers either in the dorsal horn of the spinal cord or in subcutaneous tissue. Endomorphin-1 and endomorphin-2 were expressed in immune cells (macrophage/monocytes) in the medullary region of the popliteal lymph nodes. The proportion of immunocytes (macrophage/monocytes, lymphocytes) containing endomorphin-1 and endomorphin-2 was increased in inflamed lymph nodes and subcutaneous paw tissue of animals with local inflammatory pain. Taken together, the upregulation of MOR and of its endogenous ligands endomorphin-1 and endomorphin-2 in immunocytes suggests an involvement of these opioid peptides in the peripheral control of inflammatory pain.

A new acute inflammatory syndrome related to the introduction of mycophenolate mofetil in patients with Wegener's granulomatosis

Mycophenolate mofetil (MMF) is increasingly used for prevention of allograft rejection and to treat immune disorders. We report the development of an acute inflammatory syndrome in two patients with Wegener's granulomatosis after MMF was introduced, because of persistent renal and systemic disease activity despite cyclophosphamide treatment. Within 1 week both patients developed an acute inflammatory syndrome, characterized by fever, arthralgias and muscle pain. No infection could be detected and no indications for increased Wegener's activity were present. MMF was stopped resulting in a rapid and complete resolution of the syndrome. A rechallenge with 2 g of MMF in the second patient resulted in a relapse of the syndrome within 4 days. There was an association between symptoms and increased levels of mycophenolic acid (MPA) acyl glucuronide and serum interleukin-6, suggesting the induction of inflammatory cytokines by MPA acyl glucuronide as the cause of the syndrome. Therefore, special attention should be given to side effects such as fever, arthralgias and muscle pain when treating patients with Wegener's granulomatosis during the active phase. Because this side effect of MMF may also occur after solid organ transplantation and in other immune disorders, pharmacokinetic profiling of MPA and MPA acyl glucuronide is needed in future studies with MMF.

Heritability of nociception. III. Genetic relationships among commonly used assays of nociception and hypersensitivity

We and others have previously demonstrated that nociception in the mouse is heritable. A genetic correlation analysis of 12 common measures of nociception among a common set of inbred strains revealed three major clusters (or 'types') of nociception in this species. In the present study, we re-evaluated the major types of nociception and their interrelatedness using ten additional assays of nociception and hypersensitivity, including: three thermal assays (tail withdrawal from 47.5 degrees C water or -15 degrees C ethanol; tail flick from radiant heat), two chemical assays of spontaneous nociception (bee venom test; capsaicin test) and their subsequent thermal hypersensitivity states (including contralateral hypersensitivity in the bee venom test), a mechanical nociceptive assay (tail-clip test), and a mechanical hypersensitivity assay (intrathecal dynorphin). Confirming our earlier findings, the results demonstrate distinct thermal and chemical nociceptive types. It is now clear that mechanical hypersensitivity and thermal hypersensitivity are genetically dissociable phenomena. Furthermore, we now see at least two distinct types of thermal hypersensitivity: afferent-dependent, featuring a preceding significant period of spontaneous nociceptive behavior associated with afferent neural activity, and non-afferent-dependent. In conclusion, our latest analysis suggests that there are at least five fundamental types of nociception and hypersensitivity: (1) baseline thermal nociception; (2) spontaneous responses to noxious chemical stimuli; (3) thermal hypersensitivity; (4) mechanical hypersensitivity; and (5) afferent input-dependent hypersensitivity.