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At least 307 records · Page 17Linked to original sources
PubMed2004

Ectopic posterior pituitary high signal in preoperative and postoperative macroadenomas: dynamic MR imaging.

BACKGROUND AND PURPOSE: In patients with macroadenoma, posterior pituitary high signal (PPHS) on T1-weighted magnetic resonance (MR) imaging is sometimes observed in an ectopic location. The present study compared incidences of ectopic PPHS before and after macroadenoma surgery using MR imaging, including dynamic MR imaging to ascertain whether this ectopic change is irreversible. MATERIALS AND METHODS: MR imaging was performed preoperatively in 111 cases of macroadenoma, and then repeated more than 1-year postoperatively in 47 patients. Enhancement of PPHS was assessed using dynamic MR imaging. Areas of enhanced hyperintensity were considered true PPHS, and the relationship between presence and location of true PPHS and adenoma volume was analyzed. Moreover, changes in the presence and location of true PPHS were ascertained among the patients who underwent postoperative follow-up MR imaging. RESULTS: Preoperatively, PPHS was seen only in the normal location in 29 patients (Group A: 26.1%). High signal was detected only in an ectopic location in 58 patients, and early enhancement of this ectopic high signal was confirmed by dynamic MR imaging in 56 patients (Group B: 50.5%). No PPHS was observed in 24 patients (Group C: 21.6%). Adenoma volume was significantly greater for Group B than for Group A (p<0.001). Among the Group B patients who underwent MR imaging postoperatively (n=31), the location of PPHS was not changed, except for two patients in whom PPHS was absent. Postoperatively, PPHS was not observed in the normal location in any patient in the Group B. CONCLUSIONS: Greater volume of adenoma is associated with a higher incidence of ectopic PPHS, and the ectopic change is irreversible.

Adenoma↗
PubMed2004

Cyclooxygenase-2 selective inhibitor prevents implantation of eutopic endometrium to ectopic sites in rats.

OBJECTIVE: To evaluate Cox-2 inhibition on surgically induced endometriosis in rats. DESIGN: Prospective, randomized study SETTING: Academic facility. ANIMAL(S): Seventy adult female Sprague-Dawley rats. INTERVENTION(S): Uterine fragments were implanted into abdominal peritoneum with suture (site A), and/or into the pelvic cavity without suture (site B). Oral gavage of Cox-2 inhibitor (5 mg/kg/day, twice/day) was started 4 weeks postimplantation (protocol-1), after implantation (protocol-2), or beforehand (protocol-3). Controls received vehicle. Immunohistochemistry evaluated Cox-2 expression after treatment. MAIN OUTCOME MEASUREMENT(S): Presence and size of ectopic implants after treatment. RESULT(S): Protocol-1: After 4 weeks' treatment, size of ectopic implants (site A) was significantly reduced compared with pretreatment size. After 8 weeks' treatment, no ectopic implants were detected in 2 (40%, site A) and 3 (60%, site B) rats. Protocol-2: After 2 weeks' treatment, no ectopic implants were detected in 3 (50%, site A) and 2 (33%, site B) rats. After 4 weeks' treatment, no ectopic implants were detected in 3 (50%, site A) and 3 (50%, site B) rats. Protocol-3: After 2 or 4 weeks' vehicle-only treatment, ectopic implants were in all rats (site B). CONCLUSION(S): Cox-2 selective inhibition was effective in a rat model of endometriosis, particularly in prevention of ectopic implants.

Animals↗
PubMed2006

The effects of experimental neurolysis on ectopic firing in a rat chronic constriction nerve injury model.

PURPOSE: We studied the effects of experimental neurolysis on ectopic firing in a rat chronic constriction nerve injury (CCI) model. METHODS: Sixteen Wistar rats were used as CCI models; 8 in a neurolysis group and 8 in a sham operation group. Eight additional Wistar rats were used in a normal control group. The CCI model was created by loosely ligating the sciatic nerve with 4-0 chromic gut sutures. Seven days after surgery the same portion of the sciatic nerve, now embedded in scar tissue, was exposed. For the neurolysis group all sutures and scar tissue around the nerve were removed, and for the sham operation group only exposure of the sciatic nerve embedded in scar tissue was performed. Fourteen days after the first surgery the spinal cords of all animals in the 3 groups were transeated at the most rostral level of the spinal cord and ectopic firing was recorded antidromically from the sural nerve. The spontaneous ectopic firing frequency and the firing pattern at rest and the ectopic firing frequency under a hypoxic condition were analyzed. RESULTS: The ectopic firing frequency in the neurolysis group was significantly lower than that of the sham operation group but higher than that of the normal control group. Also the appearance rate of an on-off pattern was 0% in the neurolysis and normal control groups and 38% in the sham operation group. Finally the accumulated number of ectopic firings under a hypoxic condition was significantly smaller in the neurolysis and normal control groups than that of the sham operation group. CONCLUSIONS: Experimental neurolysis significantly improved the abnormal ectopic firing frequency and on-off firing pattern in the injured nerve of the CCI model. These findings may explain the efficacy of neurolysis on sensory symptoms such as numbness or spontaneous pain in chronic compression neuropathy.

Animals↗
PubMed2005

Hyperpolarization-activated, cation-nonselective, cyclic nucleotide-modulated channel blockade alleviates mechanical allodynia and suppresses ectopic discharge in spinal nerve ligated rats.

UNLABELLED: Abnormal spontaneous firing is well described in axotomized sensory neurons and likely contributes to nerve injury-induced pain. The hyperpolarization-activated current I(h) initiates spontaneous, rhythmic depolarization in the sinoatrial node and central neurons. This study was undertaken to investigate the possible contribution of I(h) to primary afferent ectopic discharge and pain behavior in nerve-injured rats. Nerve injury was produced by tight ligation of lumbar spinal nerves (L5/6). Two weeks later, rats showed marked mechanical allodynia. Withdrawal thresholds were measured before and after administration of saline or the specific I(h) antagonist ZD7288 (1, 3, or 10 mg/kg, intraperitoneally). ZD7288 dose-dependently reversed mechanical allodynia. In a second experiment, we performed both in vivo and in vitro extracellular single unit recordings from teased dorsal root fascicles. Intravenous infusion (2.5 or 5 mg/kg) of ZD7288 during a period of 10 minutes significantly blocked ectopic discharges in vivo. Perfusion (25 to 100 mumol/L) of ZD7288 for 5 minutes in vitro almost completely blocked ectopic discharges from large myelinated fibers (Abeta) while partially suppressing ectopic discharge from thinly myelinated fibers (Adelta). We conclude from these data that in axotomized sensory neurons, a ZD7288-sensitive current contributes to spontaneous discharges in myelinated fibers. Thus, I(h) might substantially contribute to the pathophysiology of nerve injury-related neuropathic pain. PERSPECTIVE: The current study investigated the mechanism of abnormal spontaneous discharges (ectopic discharges) from axotomized sensory afferents. Ectopic discharges are a main driving source of nerve injury-induced neuropathic pain. Understanding the mechanism of ectopic discharges and identifying how to control them will be useful toward developing new therapies.

Animals↗
PubMed2003

Low-level ectopic expression of Fushi tarazu in Drosophila melanogaster results in ftz(Ual/Rpl)-like phenotypes and rescues ftz phenotypes.

The protein encoded by the Drosophila pair-rule gene fushi tarazu (ftz) is required for the formation of the even-numbered parasegments. Here we analyze the phenotypes of ectopic expression of FTZ and FTZ protein deletions from the Tubulin alpha1 (Tubalpha1) promoter. Fusion of ftz to the Tubalpha1 promoter resulted in low-level ectopic expression of FTZ relative to FTZ expressed from the endogenous ftz gene. The effects of ectopic expression of four FTZ proteins, FTZ(1-413) (full length wild-type FTZ), FTZ(delta257-316) (a complete deletion of the HD), FTZ(delta101-150) (a deletion that includes the major FTZ-F1 binding site) and FTZ(delta151-209) were determined. Ectopic expression of FTZ(1-413), FTZ(delta257-316) and FTZ(delta101-151) did not result in an anti-ftz phenotype; however, ectopic expression of FTZ(1-413), and FTZ(delta257-316) did result in a ftz(Ual/Rpl)-like phenotype. In addition, low-level ectopic expression of FTZ(1-413) and FTZ(delta257-316) rescued ftz phenotypes. This was an important observation because the even-numbered parasegment pattern of FTZ expression is considered important for normal segmentation. Therefore, the rescue of ftz phenotypes by low-level FTZ expression in all cells of the embryo suggests that the even-numbered parasegment expression pattern of FTZ is not the sole factor restricting FTZ action. Low-level ectopic expression of FTZ(delta151-209) resulted in the anti-ftz phenotype and rescued hypomorphic ftz-f1 phenotypes indicating that FTZ(delta151-209) is a hyperactive FTZ molecule. Therefore, the region encompassing amino acids 151-209 of FTZ is required in some manner for repression of FTZ activity. These results are discussed in relation to the current understanding of the mechanism of FTZ action.

Alleles↗
PubMed2001

Ultrastructural features and synaptic connections of hilar ectopic granule cells in the rat dentate gyrus are different from those of granule cells in the granule cell layer.

Several investigators have shown the existence of dentate granule cells in ectopic locations within the hilus and molecular layer using both Golgi and retrograde tracing studies but the ultrastructural features and synaptic connections of ectopic granule cells were not previously examined. In the present study, the biocytin retrograde tracing technique was used to label ectopic granule cells following injections into stratum lucidum of CA3b of hippocampal slices obtained from epileptic rats. Electron microscopy was used to study hilar ectopic granule cells that were located 20-40 microm from the granule cell layer (GCL). They had ultrastructural features similar to those of granule cells in the GCL but showed differences, including nuclei that often displayed infoldings and thicker apical dendrites. At their origin, these dendrites were 6 microm in diameter and they tapered down to 2 microm at the border with the GCL. Both biocytin-labeled and unlabeled axon terminals formed exclusively asymmetric synapses with the somata and proximal dendrites of hilar ectopic granule cells. The mean number of axosomatic synapses for these cells was three times that for granule cells in the GCL. Together, these data indicate that hilar ectopic granule cells are postsynaptic to mossy fibers and have less inhibitory input on their somata and proximal dendrites than granule cells in the GCL. This finding is consistent with recent physiological results showing that hilar ectopic granule cells from epileptic rats are more hyperexcitable than granule cells in the GCL.

Animals↗
PubMed1987

Isthmic ectopic pregnancy and salpingitis isthmica nodosa.

Two hundred eighty-five charts were reviewed from patients who underwent surgery for ectopic pregnancy. Excluded were patients with previous tubal reparative surgery, linear salpingotomy, or failed sterilization. The incidence of isthmic ectopic pregnancy in the remaining 255 cases was 15.3%. The association of salpingitis isthmica nodosa (SIN) and isthmic ectopic pregnancy was determined by review of resected tubal segments. SIN was noted in 17 of 37 cases (45.9%) of isthmic ectopic pregnancy. SIN places the patient at risk for recurrent ectopic pregnancy or infertility. Recommended conservative management of isthmic ectopic pregnancy is segmental resection with postoperative emphasis on documentation of SIN when present. Postoperative hysterosalpingography is recommended with an abnormal contralateral tube or when SIN is noted in the resected tubal segment. Management options after an isthmic ectopic pregnancy when future fertility is desired are presented.

Fallopian Tubes↗
PubMed1999

Unusual anatomic presentation of ectopic ureteroceles.

The authors describe four patients with unusual anatomic presentation of ectopic ureteroceles and their surgical treatment. Over a 3-year period, four cases of unusual ectopic ureteroceles were encountered. A 6-month-old girl had a complex cloacal anomaly with an ectopic ureterocele within the cloaca. A 10-year-old boy had two large diverticuli within an ectopic ureterocele combined with a blind-ending ipsilateral ureter. A 3-year-old girl had an ectopic ureterocele combined with a periureteral diverticulum and a completely duplicated ipsilateral kidney. A 4-year-old girl was found to have a vaginal ectopic ureterocele. Despite thorough radiological investigation in all patients, a correct assessment of the anatomic defect was achieved only by surgical exploration or endoscopic evaluation. If preoperative radiological evaluation is equivocal, a high index of suspicion and intraoperative recognition of an unusual anatomic presentation of the ectopic ureterocele are essential for appropriate management and a successful outcome.

Child↗
PubMed1986

Propafenone for the treatment of refractory complex ventricular ectopic activity.

The results of therapy with propafenone were evaluated in 45 patients with complex ventricular ectopic activity that had been refractory to a mean of 3.8 antiarrhythmic drugs. The cardiac diagnoses were ischemic heart disease (in 16 patients), cardiomyopathy (in 7), mitral valve prolapse (in 7), mitral valve prolapse (in 7), idiopathic ventricular ectopic beats (in 6), valvular heart disease (in 5), and hypertension (in 4). The frequency of ventricular ectopic beats was established after therapy with antiarrhythmic agents had been discontinued. Patients then received propafenone during a dose-ranging protocol. An effective response was defined as a reduction in total ventricular ectopic beats of 80% or more. During dose ranging, therapy failed in four patients because of side effects, in eight because of a reduction in ventricular ectopic beats of less than 80%, and in three because of an aggravation of the arrhythmia. Thirty patients had a reduction in total ventricular ectopic beats of 80% or more. During a mean follow-up of 12.4 months, therapy failed in 1 patient because of sustained ventricular tachycardia and in 7 because of intolerable side effects; 22 patients continued to receive propafenone. PR and QRS intervals were significantly prolonged (P = 0.001), but the corrected QT interval and the heart rate were unchanged. The mean trough plasma level of propafenone associated with an effective response was 756 ng/ml, and that associated with intolerable side effects was 920 ng/ml. Thus, in patients with refractory complex ventricular ectopic beats, propafenone was effective and well tolerated initially in 67% of patients and during long-term administration in 49%, and toxicity was minor in most patients.

Adult↗
PubMed1993

Osteopontin mRNA expression during bone resorption: an in situ hybridization study of induced ectopic bone in the rat.

To study the relationship between the expression of osteopontin mRNA and ectopic bone formation and resorption, in situ hybridization using 35S-labeled RNA probes was performed on ectopic bone that was induced in an experimental rat model. The expression of type I collagen and osteocalcin in this ectopic bone was also examined. After 6-week-old male Wistar rats were injected intravenously with colchicine at a dose of 1 mg/kg, trabecular bone-like ectopic calcified tissue had formed in the medial bone marrow cavity of the tibia on day 4, and then continued to increase progressing forward to the distal cavity. On day 8 peak growth was attained, after which it was resorbed within 4 days as a result of osteoclast recruitment. Subsequent in situ hybridization of sections of the ectopic bone at 4, 6, 8, and 10 days after this colchicine treatment revealed that high levels of the type I collagen mRNA were expressed in the osteoblasts of the mineralized ectopic bone surface, not only during the formation period but also during bone resorption. Although osteocalcin showed no specific signals throughout the experiments, osteopontin mRNA was expressed temporarily at day 10 during the initial phases of ectopic bone resorption, primarily in both osteoblasts and osteocytes and further in some osteoclasts. These results suggest that de novo synthesis of osteopontin is closely associated with bone resorption and could possibly be required to initiate and mediate this biological process.

Animals↗
PubMed2000

Factors that may predispose to rupture of tubal ectopic pregnancy.

OBJECTIVE: The purpose of our study was to evaluate factors that may predispose to rupture of tubal ectopic pregnancy. The study included 99 cases of ectopic pregnancies that were treated during the 5-year period 1992-1996. RESULTS: It was found that: (1) tubal rupture is encountered more often in women with no history of ectopic pregnancy and in those who have full-term pregnancy, suggesting that ectopic pregnancy is less suspected in these women; (2) tubal rupture is encountered less often in lower age ectopic pregnancy; and (3) serum beta-hCG level does not predict tubal rupture. CONCLUSIONS: Rupture of the tube is more often observed in women with a history of ectopic pregnancy and in women with full-term pregnancy. Such observations suggest that ectopic pregnancy is less suspect in these cases.

Adult↗
PubMed2000

Characteristics of ectopic discharges in a rat neuropathic pain model.

Injured afferent neurons produce spontaneous activity that is generated away from the normal impulse generation site. Since this activity, referred to as ectopic discharges, may play a significant role in neuropathic pain, it is important to systematically analyze the activity in various pain states. The present study used the segmental spinal nerve injury model of neuropathic pain to quantify the ectopic discharges from injured afferents in the neuropathic rat under various conditions. All aspects of measured ectopic discharges declined as postoperative time lengthened. Neuropathic pain behaviors declined in a similar fashion over the same time period. Surgical sympathectomy on neuropathic animals lowered the level of ectopic discharges along with neuropathic pain behaviors. The data indicate that the level of ectopic discharges is well correlated with that of pain behaviors in a rat neuropathic pain model, and this reinforces the supposition that ectopic discharges are important to the maintenance of neuropathic pain behaviors. The data suggest that there are two components of ectopic discharge generator mechanisms: sympathetically dependent and sympathetically independent components.

Action Potentials↗
PubMed1997

Slow sodium-dependent potential oscillations contribute to ectopic firing in mammalian demyelinated axons.

Ectopic action potentials can arise at regions of axonal demyelination, and are believed to contribute to a range of symptoms in patients with demyelinating conditions such as multiple sclerosis. The mechanism(s) by which the ectopic impulses are generated are uncertain. We have previously shown that such ectopic activity can result from inward potassium currents. Paradoxically, the potassium channel blocking agent 4-aminopyridine (4AP) can sometimes cause ectopic activity in demyelinating lesions. To study this phenomenon we have made intra-axonal recordings of ectopic activity in demyelinated axons, both in the presence and absence of 5 mM 4AP. 4AP promoted a pattern of firing which was observed, albeit less frequently, in demyelinated axons in the absence of this drug, namely trains of single impulses, or trains of short, high-frequency bursts of impulses. When recorded close to the demyelinated lesion, the impulses were generated by an underlying, almost sinusoidal oscillation of the membrane potential. This oscillation was abolished by the sodium channel blocking agent tetrodotoxin (0.1-1 microM). We conclude that the ectopic spiking induced by 4AP is generated by membrane potential oscillations associated with the site of demyelination. The sodium-dependent current underlying these oscillations, together with the prolonged inward potassium currents which we have previously described, may contribute to the generation of ectopic discharges in a range of disorders of myelinated axons.

4-Aminopyridine↗
PubMed1983

Mechanisms of fixed coupled ventricular ectopic complexes.

Mechanisms of fixed coupled ventricular ectopic complexes (VECs) were studied in the monitoring ECGs of 7 patients with the aid of a special purpose computer. Over 80% of the 4500 fixed coupled VECs studied had coupling intervals restricted to a range of 120 ms. The actual coupling interval varied between subjects. No special part of diastole exhibited the property of fixation. In five patients there was evidence of parasystole despite the fixed coupling. In two of these the ectopic period was clearly different from the sinus period. In the other three a difference was evident between inter-ectopic and sinus intervals, but the ectopic period could not be determined due to absence of short inter-ectopic intervals. Absence of some intervals was due to exit block or consistent coincidence of ectopic stimuli with ventricular refractoriness. In all five patients the inter-ectopic intervals showed progressive adjustment so as to become equal to a multiple of the sinus period. The coupling interval, which indicated the preferred phase relationship of the two rhythms, was altered by small changes in the sinus period. These adjustments were greater manifestations of the synchronising effects, already described, of sinus rhythm on a ventricular parasystolic rhythm. By contrast the VECs of two other patients exhibited very different characteristics. In one, the VECs restricted to 40 ms after the T wave in early diastole were probably due to ventricular re-excitation. In the other, runs of idioventricular rhythm and VECs in late diastole were due to an escape pacemaker rhythm.

Aged↗
PubMed2001

Bcl-2 expression as a novel immunohistochemical marker for ruptured tubal ectopic pregnancy.

Programmed cell death by apoptosis occurs in fetal and maternal tissues during early pregnancy and plays an important role during implantation, decidualization, and in fetal development. In the regulation of apoptosis, bcl-2 is one of the central controlling genes, and acts by protecting the cell against apoptosis. It is postulated that invasiveness of ectopic trophoblast towards and through the muscularis zone of the tubal wall consequently leading to tubal rupture might be due to disturbed regulation of apoptosis. By means of immunohistochemistry and a computerized image analysis, bcl-2 immunostaining was localized and quantified in 36 randomly selected paraffin-embedded ectopic trophoblast tissue specimens collected from women undergoing surgery for ruptured (n = 18) and non-ruptured (n = 18) tubal ectopic pregnancies. Immunostaining was found in the villi syncytiotrophoblast in all patients, while the percentage of positive bcl-2 immunostained area (%PA) (P = 0.0009) and staining intensity (P = 0.0042) were consistently greater in the group of ruptured ectopic pregnancies. Including the variables %PA and saturation into a logistic regression model for a probability threshold of 0.5 (<0.5 = non-ruptured ectopic pregnancy, >0.5 = ruptured ectopic pregnancy) to identify tubal rupture, a sensitivity and specificity of 94.4% were found. It is suggested that elevated bcl-2 immunostaining in the syncytiotrophoblast layer reflects unlimited cell survival of ectopic trophoblast and could lead to the establishment of a circulating marker for tubal rupture.

Adult↗
PubMed2003

Ectopic breast tissue as a possible cause of false-positive axillary sentinel lymph node biopsies.

Epithelial inclusions representing ectopic breast tissue are uncommonly seen in axillary lymph nodes. The extensive histopathologic examination of axillary sentinel lymph nodes of patients with breast carcinoma may increase the chances to encounter tiny foci of ectopic breast tissue, which may be misinterpreted as (micro)metastatic disease and lead to unwarranted completion of axillary dissection and to inaccurate staging and improper adjuvant treatments for the patients. Here we report on seven cases of ectopic breast tissue in axillary sentinel lymph nodes. In three cases there were coexistent micrometastases, and in the remaining cases the ectopic tissue was not associated with metastatic disease. The ectopic breast tissue showed remarkably varied morphologic features, including apocrine metaplasia and proliferative changes indistinguishable from those occurring in sclerosing adenosis and florid epithelial hyperplasia of the breast. A peripheral layer of myoepithelial cells was consistently detected in the ectopic glands and ducts. Besides awareness and purely morphologic criteria, a false-positive identification of these inclusions as metastatic carcinoma may be avoided by the use of immunohistochemical reactions for the localization of specific markers of the myoepithelial cell component, which is associated with the ectopic breast tissue.

Adult↗
PubMed1999

The role of 99mtechnetium dimercapto-succinic acid renal scans in the evaluation of occult ectopic ureters in girls with paradoxical incontinence.

PURPOSE: We describe the use of 99mtechnetium (Tc) dimercapto-succinic acid (DMSA) renal scintigraphy to document poorly functioning and/or ectopic renal units associated with occult ectopic ureters. MATERIALS AND METHODS: During the last 8 years 6 toilet-trained girls were referred for lifelong continuous urinary dribbling. Initial radiological evaluation included renal and bladder sonography in 6, excretory urography in 4, a mercaptoacetyltriglycine-3 renal scan in 1 and cystovaginoscopy in 2. Ultimately a 99mTc-DMSA renal scan was performed in all 6 girls before surgical intervention. RESULTS: Sonography failed to establish the diagnosis of ureteral ectopia in all cases, and revealed a normal solitary kidney in 3, normal kidneys in 1, an apparently uncomplicated unilateral duplication without hydroureteronephrosis in 1 and a contralateral uncomplicated duplication in 1. Excretory urography in 4 cases was inconclusive and showed a solitary kidney in 1, ipsilateral duplication without a normal appearing upper pole collecting system in 1, contralateral uncomplicated duplication in 1 and normal kidneys in 1. A mercaptoacetyltriglycine-3 renal scan in another girl with a solitary kidney on sonography failed to demonstrate a contralateral small ectopic kidney. Cystovaginoscopy performed in 2 patients by other pediatric urologists was nondiagnostic. 99mTc-DMSA renal scintigraphy was diagnostic in all 6 cases, and revealed a small poorly functioning ectopic kidney in 3 and a poorly functioning dysplastic upper pole moiety in 3, which were consistent with a diagnosis of ureteral ectopia. An ectopic ureter was confirmed by cystoscopic and surgical findings in all girls. CONCLUSIONS: 99mTc-DMSA renal scintigraphy reliably detects and localizes hypoplastic ectopic kidneys and poorly functioning upper pole moieties associated with occult ectopic ureters in girls with continuous urinary leakage.

Child↗
PubMed2001

Chronic effects of the nucleus pulposus applied to nerve roots on ectopic firing and conduction velocity.

STUDY DESIGN: This study analyzed the effects of the autologous nucleus pulposus (NP) on nerve root function using electrophysiologic methods. OBJECTIVES: To investigate the chronic effects of the NP applied to nerve roots and dorsal root ganglions (DRGs) on ectopic firing and nerve conduction velocity. SUMMARY OF BACKGROUND DATA: It was reported that ectopic firing in DRGs is involved in abnormal sensation such as sciatica and that ectopic firing was increased shortly after application of the NP to nerve roots. It was also reported that various inflammatory reactions occur around herniated NP clinically, which may affect nerve roots. However, the chronic action of NP on ectopic firing in the stage of inflammatory reaction is unknown. METHODS: Forty-six rats were divided into three groups: nucleus pulposus (NP) group, sham group, and control group. In the NP group the autologous NP was applied to L4 and L5 nerve roots. At 1, 2, 4, and 8 weeks after treatment, antidromically propagated ectopic firing from nerve roots was recorded from the sural nerve, and the nerve conduction velocity between the cauda equina and sciatic nerve was analyzed. The frequencies of ectopic firing in the three groups were compared. The ratios of the nerve conduction velocities on the treatment side and opposite side were compared between the NP and sham groups. RESULTS: The frequency was significantly higher in the NP group than in the sham group at 4 weeks. There were no significant differences among the three groups at 8 weeks. There was no significant difference in the treatment side/opposite side ratio of nerve conduction velocity between the NP and sham groups at any time point. CONCLUSIONS: Increased ectopic firing in the stage of inflammatory reaction to NP may be related to abnormal sensation.

Animals↗