Comparison of Bone Evaluation and Metal Artifact between Photon-Counting CT and Five Energy-Integrating-Detector CT under Standardized Conditions Using Cadaveric Forearms.

BACKGROUND: To compare the potential of various bone evaluations by considering photon-counting CT (PCCT) and multiple energy-integrating-detector CT (EIDCT), including three dual-energy CT (DECT) scanners with standardized various parameters in both standard resolution (STD) and ultra-high-resolution (UHR) modes. METHODS: Four cadaveric forearms were scanned using PCCT and five EIDCTs, by applying STD and UHR modes. Visibility of bone architecture, image quality, and a non-displaced fracture were subjectively scored against a reference EIDCT image by using a five-point scale. Image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also compared. To assess metal artifacts, a forearm with radial plate fixation was scanned by with and without Tin filter (Sn+ and Sn-), and virtual monoenergetic image (VMI) at 120 keV was created. Regarding Sn+ and VMI, images were only obtained from the technically available scanners. Subjective scores and the areas of streak artifacts were compared. RESULTS: PCCT demonstrated significantly lower noise (p < 0.001) and higher bone SNR and CNR (p < 0.001) than all EIDCTs in both resolution modes. However, there was no significant difference between PCCT and EIDCTs in almost all subjective scores, regardless of scan modes, except for image quality where a significant difference was observed, compared to several EIDCTs. Metal artifact analysis revealed PCCT had larger artifact in Sn- and Sn+ (p < 0.001), but fewer in VMIs than three DECTs (p < 0.001 or 0.001). CONCLUSIONS: Under standardized conditions, while PCCT had almost no subjective superiority in visualizing bone structures and fracture line when compared to EIDCTs, it outperformed in quantitative analysis related to image quality, especially in lower noise and higher tissue contrast. When using PCCT to assess cases with metal implants, it may be recommended to use VMIs to minimize the possible tendency for artifact to be pronounced.

Variations in the Extensor Pollicis Brevis-Extensor Pollicis Longus Tendon Complex.

Despite several reports on the running of the extensor pollicis brevis (EPB) tendons, the classification of tendon insertions remains ununified due to differences in reports. This diversity in tendon patterning is attributed to the process of tendon development. In this study, we assessed the running of the EPB tendons of 44 cadaver hands fixed in ethanol/formalin in detail and examined the existing classification method. The specimens were obtained from 15 women and seven men, with an average age of 86 years. Consistent with previous reports, we observed a wide diversity in the running of the EPB tendons. Further, we found that EPB tendon insertions showed diverse variations in the proportion and running of fibers, making it difficult to classify them into independent patterns. It is speculated that the EPB tendon develops through a different process than that of the muscle body of the EPB and that the entire muscle-tendon module of the EPB is evolving. The diversity of the EPB tendons observed in this study may reflect the ongoing process of evolution. In clinical practice, a wide variation in the running of the EPB tendons should be considered.

Ethylene Is Not Responsible for Phytochrome-Mediated Apical Hook Exaggeration in Tomato.

The apical hook of tomato seedlings is exaggerated by phytochrome actions, while in other species such as bean, pea and Arabidopsis, the hook is exaggerated by ethylene and opens by phytochrome actions. The present study was aimed to clarify mainly whether ethylene is responsible for the phytochrome-mediated hook exaggeration of tomato seedlings. Dark-grown 5-day-old seedlings were subjected to various ways of ethylene application in the dark as well as under the actions of red (R) or far-red light (FR). The ethylene emitted by seedlings was also quantified relative to hook exaggeration. The results show: Ambient ethylene, up-to about 1.0 µL L-1, suppressed (opened) the hooks formed in the dark as well as the ones exaggerated by R or FR, while at 3.0-10 µL L-1 it enhanced (closed) the hook only slightly as compared with the most-suppressed level at about 1.0 µL L-1. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene biosynthesis, did not enhance the hook, only mimicking the suppressive effects of ambient ethylene. The biosynthesis inhibitor, CoCl2 or aminoethoxyvinylglycine, enhanced hook curvature, and the enhancement was canceled by supplement of ethylene below 1.0 µL L-1. Auxin transport inhibitor, N-1-naphthylphthalamic acid, by contrast, suppressed curvature markedly without altering ethylene emission. The effects of the above-stated treatments did not differentiate qualitatively among the R-, FR-irradiated seedlings and dark control so as to explain phytochrome-mediated hook exaggeration. In addition, ethylene emission by seedlings was affected neither by R nor FR at such fluences as to cause hook exaggeration. In conclusion, (1) ethylene suppresses not only the light-exaggerated hook, but also the dark-formed one; (2) ethylene emission is not affected by R or FR, and also not correlated with the hook exaggerations; thus ethylene is not responsible for the hook exaggeration in tomato; and (3) auxin is essential for the maintenance and development of the hook in tomato as is the case in other species lacking phytochrome-mediated hook exaggeration. A possible mechanism of phytochrome action for hook exaggeration is discussed.

[Initial report of strontium-89 chloride treatment for painful osseous metastases at Sakai Municipal Hospital].

Strontium-89 chloride has been available at our hospital for painful osseous metastases since October 2008. Of the 17 patients(22 treatments)seen until September 2010, response to initial treatment of 13 patients was analyzed. These included cancers of the lung(5 patients, 6 treatments), breast(4 patients), thyroid(2 patients, 5 treatments), liver, 1, and prostate, 1. Other treatments patients received within 1 month of Sr-89 injection were; chemotherapy, 5 patients; radiotherapy, 3 patients; and bisphosphonate, 9 patients. The treatment effects were assessed 1 month after injection, and for 11 of the 13 patients, pain-relief was obtained in a mild and gradual manner. Transient flare was frequently observed, some of which made assessment of pain-relief in 6 patients difficult. We recognized that the bone marrow function before treatment was well above the 'Optimal Treatment Manual Japan ' criteria. After treatment, bone marrow functions kept above the value of grade 2(CTCAE), and even in 5 patients with recent or concomitant chemotherapy, it remained above grade 3 of the CTCAE criteria. These results led us to the conclusion that the indication and inclusion criteria for strontium-89 chloride treatment should be patients with an earlier bone metastasis burden that is currently manifested, without too much attention to bone marrow function criteria.

Significance of light-induced hook exaggeration as reinforced by the concomitant anatomical change of germinating tomato seeds.

Progression of the apical hook of tomato, Solanum lycopersicum, exaggerated by phytochrome mediation at the early germination stage is followed in detail macroscopically and anatomically, and its proposed significance, i.e. survival by securing the seed coat release in the field, is reinforced by new findings. Furthermore, after self-release or artificial removal of the seed coat and the endosperm, no hook exaggeration occurs any more. Similar light-induced hook exaggeration (LIHE) is also found in carrot, parsley, and Cryptotaenia japonica, which share some seed characteristics with tomato. These findings also support the above-stated significance.

Light exaggerates apical hook curvature through phytochrome actions in tomato seedlings.

Contrary to the established notion that the apical hook of dark-grown dicotyledonous seedlings opens in response to light, we found in tomato (Solanum lycopersicum L.) that the apical hook curvature is exaggerated by light. Experiments with several tomato cultivars and phytochrome mutants, irradiated with red and far-red light either as a brief pulse (Rp, FRp) or continuously (Rc, FRc), revealed: the hook-exaggeration response is maximal at the emergence of the hypocotyl from the seed; the effect of Rp is FRp-reversible; fluence-response curves to a single Rp or FRp show an involvement of low and very low fluence responses (LFR, VLFR); the effect of Rc is fluence-rate dependent, but that of FRc is not; the phyA mutant (phyA hp-1) failed to respond to an Rp of less than 10(-2) micromol m(-2) and to an FRp of all fluences tested as well as to FRc, thus indicating that the hook-exaggeration response involves phyA-mediated VLFR. The Rp fluence-response curve with the same mutant also confirmed the presence of an LFR mediated by phytochrome(s) other than phyA, although the phyB1 mutant (phyB1 hp-1) still showed full response probably due to other redundant phytochrome species (e.g., phyB2). Simulation experiments led to the possible significance of hook exaggeration in the field that the photoresponse may facilitate the release of seed coat when seeds germinate at some range of depth in soil. It was also observed that seed coat and/or endosperm are essential to the hook exaggeration.

Efficacy and safety of the additional bepridil treatment in patients with atrial fibrillation refractory to class I antiarrhythmic drugs.

BACKGROUND: Bepridil has multiple ion-channel blocking effects and is expected to be useful for managing atrial fibrillation (AF). The purpose of this study was to clarify the efficacy and safety of additional treatment with bepridil in patients with AF who had been treated with class I antiarrhythmic drugs (AADs). METHODS AND RESULTS: Bepridil (50-200 mg/day) was given to 76 patients with either paroxysmal (n=49) or persistent AF (n=27). All patients had been treated with class I AADs (1.9+/-0.9 drugs/patient) that failed to control the AF. With the addition of bepridil, the frequency of symptomatic AF episodes decreased to less than 10% in 38 (78%) patients with paroxysmal AF, and sinus rhythm was restored within 3 months and maintained during the follow-up in 20 (74%) patients with persistent AF. Efficacy was usually obtained with a small to moderate dose (50-150 mg/day) of bepridil. During a mean follow-up period of 27+/-22 months, no potential complications occurred in any of the patients. CONCLUSIONS: The addition of bepridil to class I AADs is effective and safe for AF, but careful observation using periodic ECG recordings is essential for avoiding torsades de pointes caused by QT prolongation.

Ablation of idiopathic ventricular tachycardia in two separate regions of the outflow tract: prevalence and electrocardiographic characteristics.

Few studies have clarified the prevalence and characteristics of idiopathic outflow tachycardia (OT-VT) with an altered QRS morphology after radiofrequency catheter ablation (RFCA), requiring additional RFCA applications at a different portion of the outflow tract (OT) to abolish the OT-VT. Among 344 patients (97 VTs and 247 premature ventricular contractions), 12 (3.5%; VTs-7, PVCs-5; 6 women) had dynamic QRS morphology changes following the RFCA, requiring additional RFCA applications at a different portion to abolish the OT-VT. In 8 of 12 patients (67%), this phenomenon occurred following RFCA at right (RVOT; n = 7) or left ventricular (LVOT; n = 1) endocardial sites of the OT: The second OT-VT was consistently associated with an increase in the R-wave amplitude in the inferior leads, and in five it was finally abolished by RFCA at the left sinus of Valsalva (LSV). Conversely, in four patients (33%), the second OT-VT appeared after RFCA at the LSV: two required additional RFCA applications at the LVOT to abolish the second OT-VT, and one at the RVOT, and all were associated with a decrease in the R-wave amplitude in the inferior leads. This kind of dynamic QRS morphology change was often observed when RFCA was applied to either the first or second OT-VT at a right or left ventricular endocardial site, with the other site being the LSV. A detailed continuous observation of the QRS morphology, especially of the R-wave in the inferior leads, is important for identifying changes in the QRS morphology during RFCA.

Left atrial catheter ablation promotes vasoconstriction of the right coronary artery.

BACKGROUND: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA. METHODS: We studied 20 patients with drug-refractory AF who underwent LACA, performed to encircle the left- and right-sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance. Quantitative coronary angiography was performed before and after LACA, and we analyzed the minimal lesion diameter (MLD) of the proximal segment of the coronary arteries, and the basal tone, the baseline percent constriction versus maximal dilation after nitroglycerin administration. RESULTS: No significant difference was observed in MLD or basal tone of the left coronary arteries after LACA. However, in the right coronary artery (RCA), the basal MLD was smaller (P < 0.01) and the basal tone was greater (P < 0.05) after than before LACA. No correlation was found between the baseline MLD or tone of the RCA and total amount of radiofrequency energy delivered or procedure duration. In 75% of RCA, the baseline MLD was smaller after than before LACA, which was significantly higher (P < 0.01) than observed in the left coronary arteries (38%). CONCLUSION: Vasoconstriction was promoted in the RCA shortly after LACA, which may explain the variant angina reported after LACA.

Plasma natriuretic peptide concentrations as a predictor for successful catheter ablation in patients with drug-refractory atrial fibrillation.

BACKGROUND: The concentrations of atrial and brain natriuretic peptides (ANP and BNP) are elevated in patients with atrial fibrillation (AF), but the usefulness of their measurement before and after AF ablation has not been reported. METHODS AND RESULTS: The concentrations of the natriuretic peptides were evaluated in 54 patients undergoing catheter ablation for drug-resistant paroxysmal and persistent AF without heart failure. Based on the outcome, the patients were divided into 2 groups: successful (n=42) or failure (n=12). All patients were asked to keep a log of the duration and frequency of their symptoms and underwent 24-h ECG monitoring at least once after the ablation. The plasma BNP and ANP concentrations, most of which were well below the heart failure range, exceeded the normal range in 69% and 26% of the patients, respectively. The BNP concentration decreased after ablation in the success group (49+/-43 to 27+/-28 pg/ml; p<0.05), however, it was unchanged in the failure group (46+/-35 to 70+/-37 pg/ml; p=0.46). A value of the DeltaBNP (BNP after ablation - BNP before ablation) of

Maximum ventricular dyssynchrony predicts clinical improvement and reverse remodeling during cardiac resynchronization therapy.

BACKGROUND: Tissue synchronization imaging (TSI) and tissue tracking imaging (TTI) might facilitate the evaluation of ventricular dyssynchrony. METHODS: In 22 patients, TSI and TTI were performed before and < 1 month after onset of cardiac resynchronization therapy (CRT). With TSI guidance, maximum left ventricular (LV) intraventricular conduction delay (IVCDmax) was the greatest difference in time-to-peak velocity between septum and lateral wall. IVCD between the basal septum and lateral wall (IVCDbase) was also measured. Using TTI, the mean peak myocardial displacement of the basal septal and lateral walls (PMDbase), and the temporal coefficient of variation of the PMD in six LV regions (CV-PMDLV) were measured. The patients were divided into responders (whose LV end-systolic volume decreased by >/= 15% during a 27 +/- 9 months follow-up) and nonresponders. RESULTS: Before CRT, IVCDbase was similar in both groups, and remained unchanged within the 1st month of CRT in both groups. However, before CRT, IVCDmax was greater in responders than in nonresponders (P < 0.05), and decreased only in the responders during CRT (P < 0.05). No significant difference was observed in PMDbase or CV-PMDLV between the two groups, before or during CRT. CONCLUSIONS: TSI was useful to measure IVCDmax. A greater IVCDmax before CRT that decreased shortly after onset of CRT may predict long-term clinical improvement in CRT recipients.

Idiopathic ventricular arrhythmias originating from the tricuspid annulus: Prevalence, electrocardiographic characteristics, and results of radiofrequency catheter ablation.

BACKGROUND: Idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) arising from the tricuspid annulus have been reported. OBJECTIVE: The purpose of this study was to clarify the prevalence and characteristics of VT/PVCs originating from the tricuspid annulus. METHODS: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 454 patients with idiopathic VT/PVCs. RESULTS: Thirty-eight (8%) patients had VT/PVCs arising from the tricuspid annulus: 28 VT/PVCs (74%) originated from the septal portion of the tricuspid annulus and the remaining 10 (26%) from the free wall of the tricuspid annulus. QRS duration and Q-wave amplitude in each of leads V1-V3 were greater in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (all P < .01). "Notching" of the QRS complex was observed more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .01). A Q wave in lead V1 was observed more often in VT/PVCs arising from the septum of the tricuspid annulus than those from the free wall of the tricuspid annulus (P < .005). R-wave transition occurred beyond lead V3 more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .005). RF catheter ablation eliminated 90% of the VT/PVCs arising from the free wall of the tricuspid annulus but only 57% of the VT/PVCs arising from septum of the tricuspid annulus. CONCLUSION: Idiopathic VT/PVCs arising from tricuspid annulus are not rare, and the detailed origin can be determined by ECG analysis. The preferential site of origin was the septum but also could be the free wall of the tricuspid annulus.

Significance and utility of plasma brain natriuretic peptide concentrations in patients with idiopathic ventricular arrhythmias.

BACKGROUND: Secretion of B-type natriuretic peptide (BNP) appears to be regulated mainly by wall tension, and an increase in the plasma BNP concentration is considered to reflect ventricular structural and functional abnormalities. The aim of this study was to clarify the significance and utility of the measurement of the plasma BNP in the setting of idiopathic ventricular arrhythmias (I-VT/PVCs). METHODS: This study included 135 patients with symptomatic, monomorphic I-VT/PVCs (73 women; 53 +/- 17 years; 50 ventricular tachycardias [VTs], 85 premature ventricular contractions) who underwent radiofrequency catheter ablation. None had structural heart disease or renal dysfunction. RESULTS: The plasma BNP concentration exceeded the normal range (>18.4 pg/mL; high BNP concentration) in 79 patients (56%). The high BNP concentration was found more often in I-VT/PVCs originating from the left ventricle (LV; 74%) than the right ventricle (RV; 49%; P < 0.01). The plasma BNP concentration correlated with the age (P = 0.0001) and frequency of premature ventricular contractions (P < 0.0001), and left-sided I-VT/PVCs and the presence of controlled hypertension were independent predictors of a high BNP concentration (both P < 0.05). In patients with a successful ablation and high BNP concentration before the ablation, the BNP concentration decreased to the normal range in 61% of patients after ablation. In patients with a failed ablation, the BNP concentration did not decrease to the normal range after ablation in any of the patients (P < 0.0005). CONCLUSIONS: The plasma BNP concentration was elevated in about 60% of the patients with symptomatic I-VT/PVCs. Normalization of the high BNP concentration after ablation may indicate a successful ablation.

[Radiofrequency ablation for hepatocellular carcinoma and liver metastases].

We evaluated the efficacy of radiofrequency ablation (RFA) therapy for 29 patients with 36 hepatocellular carcinoma (HCC) nodules and 16 patients with 38 metastatic hepatic nodules. The mean tumor size was 26.4 mm. The primary lesions of patients with metastatic liver tumors were 9 colon cancer, 2 rectal cancer, 2 breast cancer, 2 gastric cancer, and 1 esophageal cancer. All nodules were treated using a Cool-tip RFA system. US-guided RFA was performed for 44 nodules, CT-guided RFA for 24 nodules, and intra-operative US-guided RFA for 6 nodules. In a mean observation period of 13.5 months, the mean complete ablation rate and the mean distant recurrence rate were 83.3% and 30.6% for HCC and 65.8% and 31.6% for metastatic nodules, respectively. The mean complete ablation rate of HCC was significantly higher than that of metastatic nodules (p < 0.05). The mean complete ablation rates of both HCC and metastatic hepatic nodules 3 cm or smaller in diameter were significantly higher than those of both tumors larger than 3 cm in diameter (p < 0.05). The mean distant recurrence rate of HCC in patients who have multiple nodules was 62.5% and it was significantly higher than that in patients who have a single nodule (28.6%) (p < 0.05). The mean complete ablation rate of metastatic nodules by intra-operative US guided RFA was 100% and it was statistically higher than that by other image guided RFA (p < 0.05).

Left atrial and pulmonary vein ostial ablation as a new treatment for curing persistent atrial fibrillation.

BACKGROUND: Segmental pulmonary vein (PV) isolation has been performed to eliminate paroxysmal atrial fibrillation (AF). However, this technique is not effective in most patients with persistent AF. METHODS AND RESULTS: Left atrial catheter ablation (LACA) was performed by encircling the left- and right-sided PV 1-2 cm from the ostia, guided by an electroanatomical mapping system in 16 patients with persistent AF (>1 month). Twelve patients (75%) had a history of unsuccessful transthoracic cardioversion and prophylactic antiarrhythmic drugs. Ablation lines were also created in the mitral isthmus and posterior LA. PV isolation was also performed for each PV if there were residual PV potentials after the LACA. After LACA, 38 PV (59%) were completely isolated, and complete PV isolation was achieved with only a few radiofrequency energy applications (2.7+/-2.0 min) on a narrow area of the PV ostium (24+/-15%) in the remaining PV. The mean procedure time was 200+/-38 min. During the follow-up period (17+/-3 months), 12 patients (75%) had normal sinus rhythm and were free of symptomatic AF with (n = 10) or without antiarrhythmic drugs (n = 2). One patient had a stroke just after the procedure. No other complications including PV narrowing (>50%) occurred. CONCLUSION: This approach was effective in persistent AF, however, concomitant use of antiarrhythmic drugs was often required.

Percutaneous transvenous mitral commissurotomy and radiofrequency catheter ablation in patients with mitral stenosis.

BACKGROUND: The purpose of this study was to evaluate the short- and long-term results of radiofrequency catheter ablation (RFCA) for the treatment of atrial fibrillation (AF) in patients with mitral stenosis (MS) following percutaneous transvenous mitral commissurotomy (PTMC). METHODS AND RESULTS: Four patients (2 males, age 59+/-6 years) underwent simultaneous PTMC and pulmonary vein (PV) ablation. All patient had AF and MS (2 had persistent AF >1 month, 2 had paroxysmal AF), and the mean duration of AF was 3.4+/-3.3 years. The mean left atrial dimension was 47+/-7 mm and the mean ejection fraction was 58+/-4%. After PTMC, RFCA was performed in all patients (3 underwent PV isolation and 1 had PV focal ablation). The mitral valve area increased from 1.11 +/-0.19 to 1.90+/-0.20 cm(2) (p < 0.01). The frequency of AF episodes was dramatically reduced in the 2 patients with paroxysmal AF, and the 1 with persistent AF maintained sinus rhythm, but 1 patient with persistent AF developed recurrent AF. No complications or cardiac events occurred in any of the patients. CONCLUSION: The combination of RFCA and PTMC was safe and feasible, and may be useful in patients with MS and AF.

Idiopathic premature ventricular contractions arising from the pulmonary artery: importance of mapping in the pulmonary artery in left bundle branch block-shaped ventricular arrhythmias.

A patient underwent radiofrequency (RF) catheter ablation of symptomatic idiopathic ventricular contractions (PVCs). RF energy applications at 2 sites in the right ventricular outflow tract (RVOT), where both the earliest ventricular activation and near-perfect pace mapping were obtained, did not abolish the PVC but resulted in changes in the QRS morphology of the PVC. Complete elimination of the PVC was achieved with RF energy application at a site within the pulmonary artery 13 mm above the pulmonary valve, which was greater than 20 mm away from the failed ablation sites within the RVOT.

c-Fos expression in the spinal cord after acute sacral segmental nerve stimulation.

AIMS: Sacral nerve stimulation (SNS) can provide subjective and objective relief of pelvic pain and chronic voiding symptoms, but its mechanism is poorly understood. It is well known that a noxious stimulus applied to one part of the body can reduce the response to a subsequent stimulus elsewhere in the body. This phenomenon, known as diffuse noxious inhibitory controls (DNIC), seems to be the mechanism by which pain can be reduced by concurrent noxious stimulation. METHODS: On the basis of the DNIC concept, we investigated the expression of a protein product of proto-oncogene c-Fos (c-Fos) in the rat spinal cord after acute electrical stimulation of the sacral segmental nerve with or without lower urinary tract irritation. Adult male Sprague-Dawley rats were treated either by sacral nerve stimulation (SNS) from the S1 sacral foramen or chemical irritation of the lower urinary tract (LUT) or both. Rats were perfused transcardially, and spinal cords were removed and processed for c-Fos immunohistochemistry. c-Fos expression in the central nervous system was detected by immunohistochemistry by using the avidin-biotin technique. The number of c-Fos-positive cells and their locations in the spinal cord were evaluated. RESULTS: SNS and LUT irritation resulted in significant increases in c-Fos-positive cells in L6 and S1 spinal segments. In the animals treated by SNS and LUT irritation, counts of c-Fos-positive cells in L6 and S1 segments were significantly smaller than expected. Distribution and number of c-Fos-positive cells in rats that received SNS and LUT irritation were almost the same as those induced by SNS alone in the S1 segment. CONCLUSIONS: SNS alone caused a near maximal response in c-Fos expression such that adding LUT irritation did not cause a linear increase in c-Fos. Subsequent LUT irritation could not induce additional expression of c-Fos within the spinal cord.

Spinal substance P immunoreactivity is enhanced by acute chemical stimulation of the rat prostate.

OBJECTIVES: To investigate the role substance P (SP) plays in prostatic inflammation, we evaluated SP immunoreactivity within the spinal cord after irritation of the prostate. Because alpha-adrenergic blockade attenuates nociceptor-induced pain, the effects of an alpha-adrenergic blocker on SP immunoreactivity were also evaluated. SP is considered a mediator of nociception in the spinal cord. Immunoreactivity of SP is enhanced after acute chemical stimulation of somata. METHODS: Rats received chemical irritation of the prostate with or without pretreatment with tamsulosin. They were killed after 1 hour, and immunohistochemical staining for SP was performed. SP immunoreactive areas were quantified in the dorsal spinal cord of the L5 to S2 segments. RESULTS: Chemical irritation of the prostate increased SP immunoreactive areas in the L6 to S2 segments. Enhancement was observed in the whole dorsal spinal cord regions. This enhancement was significantly attenuated by tamsulosin in the L6 and S1 segments. CONCLUSIONS: SP probably plays a significant role in mediating nociceptive processing from the prostate. Tamsulosin can attenuate nociception-induced SP upregulation within the spinal cord.