Persistent neuropathic pain influences persistence behavior in rats.

AIMS: To determine whether self-regulation can be studied successfully in a rodent model and whether persistent facial pain influences self-regulatory behavior. METHODS: Thirty male Sprague-Dawley rats, divided into two groups, (1) chronic constriction injury of the infraorbital nerve (CCI-ION) and (2) naïve, were used in a two-part behavioral paradigm of self-regulation. This paradigm consisted of both a cued go/no-go task (part one) and a persistence trial (part two). All animals were acclimated and trained for a period of 4 weeks prior to the experimental manipulation and then tested for a total of 5 weeks following experimental manipulation. Results were analyzed with t tests, one-way analysis of variance, and two-way, repeated measures analysis of variance. RESULTS: CCI-ION surgery induced significant mechanical hypersensitivity of the ipsilateral whisker pad that began 3 weeks postsurgery and persisted through the duration of the experiment (P < .001). At weeks 4 and 5 post-experimental manipulation, naïve animals demonstrated a significant decrease in lever presses during the persistence task (P < .05) compared to baseline, whereas CCI-ION animals did not (P = .55). CONCLUSION: These results suggest that persistent pain influences behavioral regulation and that animals experiencing persistent pain may have difficulty adapting to environmental demands.

Disability and health after replantation or revascularisation in the upper extremity in a population in southern Sweden - a retrospective long time follow up.

BACKGROUND: Replantation in the upper extremity is a well-established microsurgical procedure. Many have reported patients' satisfaction and functional measurements.The aim was to investigate the long time consequences as activity limitations in hand/arm, the general health and cold sensitivity after a replantation or revascularization in the upper extremity and to examine if sense of coherence (SOC) can be an indicator for rehabilitation focus. METHODS: Between 1994-2008, 326 patients needed replantation/revascularization in the upper extremity. 297 patients were followed up. Information was collected from the medical notes and by questionnaires [Quick-DASH (disability hand/arm), EuroQ-5D (general health), CISS (cold sensitivity) and SOC (sense of coherence)]. Severity of injury was classified with the modified Hand Injury Severity Score (MHISS). RESULTS: The patients [272 (84%) men and 54 (16%) women; median age 39 years (1-81 years)], where most injuries affected fingers (63%) and thumb (25%), commonly affecting the proximal phalanx (43%). The injuries were commonly related to saws (22%), machines (20%) and wood splints (20%). A direct anastomosis (30%) or vein grafts (70%) were used. The overall survival was 90%. 59% were classified as Major.Equal parts of the injuries took part during work and leisure, DASH scores at follow up were worse (p = 0.005) in the former. Twenty percent changed work and 10% retired early. Patients with early retirement were significantly older, had a more severe injury, worse disability, quality of life and functional outcome. Median DASH score was low [11.4 (0-88.6)] and correlated with severity of injury. Abnormal cold sensitivity (CISS > 50) was seen in 51/209 (24%) and they had a worse disability, quality of life, functional outcome and lower SOC. Patients with a low SOC had on the whole a worse outcome compared to patients with a high SOC and with significant differences in age, EQ-5D, Quick-DASH and CISS. CONCLUSIONS: A high MHISS, abnormal cold intolerance and a low SOC seems to be factors influencing the patients' outcome and might be relevant in the rehabilitation of the patients. Also, those who had to retire early had a worse disability, quality of life and functional outcome.

Differential implication of proinflammatory cytokine interleukin-6 in the development of cephalic versus extracephalic neuropathic pain in rats.

Responses resulting from injury to the trigeminal nerve exhibit differences compared with those caused by lesion of other peripheral nerves. With the aim of elucidating the physiopathological mechanisms underlying cephalic versus extracephalic neuropathic pain, we determined the time course expression of proinflammatory cytokines interleukin-6 (IL-6) and IL-1beta, neuronal injury (ATF3), macrophage/microglial (OX-42), and satellite cells/astrocyte (GFAP) markers in central and ganglion tissues in rats that underwent unilateral chronic constriction injury (CCI) to either infraorbital nerve (IoN) (cephalic area) or sciatic nerve (SN) (extracephalic area). Whereas CCI induced microglial activation in both models, we observed a concomitant upregulation of IL-6 and ATF3 in the ipsilateral dorsal horn of the lumbar cord in SN-CCI rats but not in the ipsilateral spinal nucleus of the trigeminal nerve (Sp5c) in IoN-CCI rats. Preemptive treatment with minocycline (daily administration of 20 mg/kg, i.p., for 2 weeks) partially prevented pain behavior and microglial activation in SN-CCI rats but was ineffective in IoN-CCI rats. We show that IL-6 can upregulate OX-42 and ATF3 expression in cultured microglia and neurons from spinal cord, respectively, as well as in the dorsal horn after acute intrathecal administration of the cytokine. We propose that IL-6 could be one of the promoters of the signaling cascade leading to abnormal pain behavior in SN-CCI but not IoN-CCI rats. Our data further support the idea that different pathophysiological mechanisms contribute to the development of cephalic versus extracephalic neuropathic pain.

[An analysis on SCL-90 of pharyngeal paraesthesia].

OBJECTIVE: To explore the mental health of the patients who suffered from pharyngeal paraesthesia, and investigate the effect of mental factors during the happening, development, therapy and turnover of the disease. METHOD: The Symptom Checklist 90 (SCL-90) was used to collect information,and all the data was dealed with SPSS 12.0. RESULT: (1) The total score of SCL-90 of pharyngeal paraesthesia was higher than the norm, and the score of positive items and average score of positive symptom were both significantly higher than the norm; (2) There was no differences between pharyngeal paraesthesia and the norm in terror factor while significant differences in the others; (3) There was no difference between male and female patients who suffered from pharyngeal paraesthesia. CONCLUSION: Compared with the normal, patients who suffered from pharyngeal paraesthesia had obvious mental symptoms, such as somatization, anxiety, depression et al.

Psychophysical evidence of hypersensitivity in subjects with interstitial cystitis.

PURPOSE: We quantified differences in somatic and visceral sensation in healthy subjects and subjects with interstitial cystitis (IC). MATERIALS AND METHODS: A total of 13 subjects with IC and 13 healthy subjects answered psychological questionnaires and underwent psychophysical testing of thermal and pressure thresholds for sensation as well as the ischemic forearm test of pain tolerance. A subset of subjects also underwent bladder sensory testing with the determination of 3 consecutive cystometrograms. Ratings of intensity and unpleasantness were determined. RESULTS: Subjects with IC were significantly more sensitive to deep tissue measures of sensation related to pressure, ischemia and bladder than healthy subjects. Cutaneous thermal pain measures were similar in the 2 groups. Psychological measures indicated higher reactivity in subjects with IC. CONCLUSIONS: Similar to other visceral pain disorders, such as irritable bowel syndrome, hypersensitivity to somatic stimuli was noted in subjects with IC. This suggests altered central mechanisms in the processing of sensory events from the bladder.

[Patient satisfaction with the outcome of surgical orthodontic intervention and effect of esthetic and functional criteria]. / Patientenzufriedenheit mit dem Endergebnis eines orthognath-chirurgischen Eingriffs und Einfluss von ästhetischen und funktionellen Kriterien.

BACKGROUND: The aim of the study was to analyze the influence of possible temporary or permanent disorders of sensation on the degree of the patient's satisfaction following an orthognathic operation. PATIENTS AND METHODS: After an average of 47 months (range: 9-141), a follow-up examination was performed in 78 women (64.5%) and 43 men (35.5%) with an average age of 24.3 years (range: 19-40) at the time of operation. In 67 cases there had been a sagittal division of the mandible, in 11 cases a Le Fort I osteotomy, in 26 cases a bimaxillary osteotomy, in 4 cases an isolated genioplasty, and in 13 cases a segmental osteotomy in the upper or the lower jaw. In the peripheral area supplied by the nerves V2 and V3 sensation was examined by the two-point discrimination test and the result related to the patients' satisfaction using the chi-square test. RESULTS AND DISCUSSION: The following qualities of sensation were recorded: anesthetic (2.7%), hypesthetic (16.6%), paresthetic (8.3%), and normesthetic (72.4%). The patients' satisfaction was rated as very satisfied in 51.3%, as satisfactory in 44.8%, and in 3.9% the patients' expectations had not been fulfilled; 75% regarded their outward appearance as markedly improved and a good 50% of the patients noted improved mastication. Therefore, three-fourths of all the patients would even be willing to be operated on again. Two-dimensional analysis, however, demonstrated only a weakly significant positive relationship between patient satisfaction and the preserved, or restored, sensation in the trigeminal region.

Neomycin and gadolinium applied to an L5 spinal nerve lesion prevent mechanical allodynia-like behaviour in rats.

In male Wistar rats, the left ventral ramus of the L5 spinal nerve (RvL5) was cut, and animals were tested for allodynia-like behaviour in response to mechanical stimuli which were applied with von Frey hairs (4.3-205 mN) to the plantar skin of the hindpaw supplied by the intact L4 spinal nerve. After surgery, allodynia-like behaviour was evoked prominently on the operated (left) side and weakly on the contralateral (right) side. Eleven sham-operated rats displayed low levels of allodynia-like behaviour on the operated side comparable to that seen contralateral to the lesion in nerve-transected animals. In 14 rats, allodynic behaviour to mechanical stimuli on either side was dose dependently and permanently reduced, after 4-32 mg of the antibiotic Nebacetin had been applied locally at the transection site immediately after cutting the nerve. The same effect was observed when one of the active compounds of Nebacetin, neomycin, but not the other, bacitracin, was applied by continuous local infusion. Allodynia-like behaviour to stimuli between 4.3 mN and 124 mN was also prevented when 1-8 mg gadolinium acetate was applied at the transection site, whereas allodynic behaviour to stimuli of 205 mN was not affected at least for the first 7 days after the lesion. Both gadolinium and Nebacetin failed to prevent allodynic behaviour when applied later than 7 h after the nerve lesion. Neither substance interfered with the development of tactile allodynia when applied to the nerve rostral to the lesion site. The results suggest that Nebacetin and gadolinium interfere with the mechanisms at the RvL5 transection site crucial for the initiation of sensitisation of dorsal horn neurones and the development of mechanical allodynia.

A behavioral model for peripheral neuropathy produced in rat's tail by inferior caudal trunk injury.

We attempted to develop an experimental animal model using rat's tail for understanding the mechanisms involving peripheral neuropathic pain. Under sodium pentobarbital anesthesia, the left inferior caudal trunk of the rat was resected between the S3 and S4 spinal nerves. Latencies of tail-flick induced by the stimulus such as warm (40 degrees C) and cold (4 degrees C) water to the tail were measured for the following 30 weeks. In addition, sensitivity of the tail to mechanical stimulation was tested with von Frey hairs on these rats. Operated rats showed abnormal sensitivity of the tail to normally innocuous mechanical and thermal (warm and cold) stimuli. We interpreted these results as signs of neuropathic pain following nerve injury. The present model offers several advantages in performing behavioral tests; (1) it is easy to apply thermal stimulation to the rat's tail using a water bottle; (2) it is easy to apply the mechanical stimulation with von Frey hairs and to localize sensitive areas in the tail; and (3) blind behavioral studies are possible due to the lack of deformity in the tail after surgery.