Survival benefits of interventional radiology and surgical teams collaboration during primary trauma surveys: a single-centre retrospective cohort study.

BACKGROUND: A team approach is essential for effective trauma management. Close collaboration between interventional radiologists and surgeons during the initial management of trauma patients is important for prompt and accurate trauma care. This study aimed to determine whether trauma patients benefit from close collaboration between interventional radiology (IR) and surgical teams during the primary trauma survey. METHODS: A retrospective observational study was conducted between 2014 and 2021 at a single institution. Patients were assigned to an embolization group (EG), a surgery group (SG), or a combination group (CG) according to their treatment. The primary and secondary outcomes were survival at hospital discharge compared with the probability of survival (Ps) and the time course of treatment. RESULTS: The analysis included 197 patients, consisting of 135 men and 62 women, with a median age of 56 [IQR, 38-72] years and an injury severity score of 20 [10-29]. The EG, SG, and CG included 114, 48, and 35 patients, respectively. Differences in organ injury patterns were observed between the three groups. In-hospital survival rates in all three groups were higher than the Ps. In particular, the survival rate in the CG was 15.5% higher than the Ps (95% CI: 7.5-23.6%; p < 0.001). In the CG, the median time for starting the initial procedure was 53 [37-79] min and the procedure times for IR and surgery were 48 [29-72] min and 63 [35-94] min, respectively. Those times were significantly shorter among three groups. CONCLUSION: Close collaboration between IR and surgical teams, including the primary survey, improves the survival of severe trauma patients who require both IR procedures and surgeries by improving appropriate treatment selection and reducing the time process.

Poisoning by abnormally high blood phenobarbital concentration treated with extracorporeal therapy.

Phenobarbital poisoning, which may cause circulatory collapse as well as respiratory arrest in severe cases, has one of the highest mortality rates among acute drug poisonings. A 58-year-old man arrived at the emergency room in a deep coma (Glasgow Coma Scale E1V1M1) after taking an unknown dose of phenobarbital which had been prescribed for his cat's seizures. Venous blood gas analysis revealed hypercapnia (PvCO2: 113.0 mmHg) and a blood phenobarbital concentration of 197.3 µg/mL. Shortly after his arrival, respiratory arrest and circulatory collapse occurred. Mechanical ventilation after intubation, intravenous noradrenaline infusion, and multiple-dose activated charcoal through a nasogastric tube was started. Six hours after arrival, blood phenobarbital concentration was abnormally elevated to 356.8 µg/mL with circulatory collapse requiring an increased dose of intravenous noradrenaline infusion (up to 0.13 µg/kg/min). Continuous renal replacement therapy including high flow continuous hemodialysis was performed until hospital day 5, during which blood phenobarbital concentration decreased to 96.2 µg/mL on hospital day 4, resulting in a sufficient resumption of spontaneous breathing and full improvement of circulatory collapse. A search of the literature revealed that the peak phenobarbital concentration in the present case exceeded those of fatal cases, as well as those of survivors of acute phenobarbital poisoning. However, the patient was successfully treated with continuous renal replacement therapy. Among modalities of extracorporeal treatment, continuous renal replacement therapy could be considered if a patient's circulation is unstable.

Successful use of the two-tube approach for the treatment of phenobarbital poisoning without hemodialysis.

Half-life of the antipsychotic vegetamin is very long, partially due to the presence of phenobarbital, and mortality due to phenobarbital poisoning is high. Here, we present the case of a 22-year-old female admitted to the emergency department with disturbed consciousness due to vegetamin overdose. Her blood phenobarbital level was elevated to 123 µg/ml. Phenobarbital undergoes enterohepatic circulation, and its retention in the intestine causes its blood levels to remain sustained. The utility of hemodialysis for drug poisoning has been previously reported; however, its efficiency is not yet established and its efficacy is low for drugs with long half-lives such as phenobarbital. Therefore, we performed a two-tube approach to adsorb phenobarbital in the intestines with activated charcoal delivered via a gastric tube and to remove the phenobarbital-adsorbed activated charcoal using whole bowel irrigation via an ileus tube 2 h later. The patient successfully eliminated the charcoal via stool, the blood phenobarbital level decreased drastically without hemodialysis, and the clinical course improved. We propose that this two-tube approach is suitable for treatment of poisoning with drugs that undergo enterohepatic circulation and have long half-lives.

Diagnostic utility of a conventional MRI-based analysis and texture analysis for discriminating between ovarian thecoma-fibroma groups and ovarian granulosa cell tumors.

OBJECTIVE: To evaluate the diagnostic utility of conventional magnetic resonance imaging (MRI)-based characteristics and a texture analysis (TA) for discriminating between ovarian thecoma-fibroma groups (OTFGs) and ovarian granulosa cell tumors (OGCTs). METHODS: This retrospective multicenter study enrolled 52 patients with 32 OGCTs and 21 OTFGs, which were dissected and pathologically diagnosed between January 2008 and December 2019. MRI-based features (MBFs) and texture features (TFs) were evaluated and compared between OTFGs and OGCTs. A least absolute shrinkage and selection operator (LASSO) regression analysis was performed to select features and construct the discriminating model. ROC analyses were conducted on MBFs, TFs, and their combination to discriminate between the two diseases. RESULTS: We selected 3 features with the highest absolute value of the LASSO regression coefficient for each model: the apparent diffusion coefficient (ADC), peripheral cystic area, and contrast enhancement in the venous phase (VCE) for the MRI-based model; the 10th percentile, difference variance, and maximal correlation coefficient for the TA-based model; and ADC, VCE, and the difference variance for the combination model. The areas under the curves of the constructed models were 0.938, 0.817, and 0.941, respectively. The diagnostic performance of the MRI-based and combination models was similar (p = 0.38), but significantly better than that of the TA-based model (p < 0.05). CONCLUSIONS: The conventional MRI-based analysis has potential as a method to differentiate OTFGs from OGCTs. TA did not appear to be of any additional benefit. Further studies are needed on the use of these methods for a preoperative differential diagnosis of these two diseases.

The effect of participation of interventional radiology team in a primary trauma survey on patient outcome.

PURPOSE: The purpose of this study was to examine the survival benefits of a workflow in which an interventional radiology (IR) team participates in a primary trauma survey on patients with hemodynamically unstable trauma. MATERIALS AND METHODS: A retrospective observational study was conducted between 2012 and 2019 at a single institution. Patients who underwent an IR procedure as the initial hemostasis were assigned to the hemodynamically stable group (HSG) or hemodynamically unstable group (HUG). The primary and secondary outcomes were survival at hospital discharge compared with the probability of survival (Ps) and the time course. RESULTS: A total of 160 patients (100 men, 60 women; median age, 57.5 years [interquartile range (IQR): 31.5-72 years]) with an injury severity score of 24 (IQR: 13.75-34) were included. A total of 125 patients were included in the HSG group and 35 patients in the HUG group. The observational survival rate was significantly greater than the Ps rate by 4.9% (95% confidence interval [CI]: 1.6-8.4%; P = 0.005) in HSG and by 24.6% in HUG (95% CI: 16.9-32.3%; P < 0.001). The observational survival rate was significantly greater than Ps in HUG than in HSG (P < 0.001). The median time to initiate IR procedures and the median procedure time in HUG were 54 min [IQR: 45-66 min] and 48 min [IQR: 30-85 min], respectively; both were significantly shorter than those in the HSG. CONCLUSION: A trauma workflow utilizing an IR team in a primary survey is associated with improved survival of patients with hemodynamically unstable trauma when compared with Ps with a shorter time course.

CXCR3 binding chemokine and TNFSF14 over expression in bladder urothelium of patients with ulcerative interstitial cystitis.

PURPOSE: We investigated the genes responsible for ulcerative interstitial cystitis by DNA microarray analysis and quantitative real-time polymerase chain reaction. MATERIALS AND METHODS: Bladder urothelial tissues were taken from a site apart from the ulcerative lesion in 9 patients with ulcerative interstitial cystitis and from a normal-looking area in 9 controls, including 7 with bladder carcinoma and 2 with benign prostatic hyperplasia. Total RNA was extracted from bladder samples and gene expression was compared between these 2 groups using Whole Human Genome DNA microarray 44K (Agilent Technologies, Santa Clara, California). Microarray data were analyzed by GeneSpring GX software and Ingenuity Pathway Analysis. Chosen genes were confirmed for altered transcription by quantitative real-time polymerase chain reaction. RESULTS: We identified 564 probes that were significantly expressed in mRNA more than 4-fold vs those in controls using volcano plot analysis (p <0.001). Further network Ingenuity Pathway Analysis of these genes showed the top 3 functions, including 1) cell-to-cell signaling and interaction, and hematological system development and function, 2) inflammatory disease and 3) cellular development. Quantitative real-time polymerase chain reaction confirmed increased mRNA expression of several genes in the bladder samples of patients with ulcerative interstitial cystitis, including CXCR3 binding chemokines (CXCL9, 10 and 11) and TNFSF14 (LIGHT). CONCLUSIONS: Our study using DNA microarray analysis followed by quantitative real-time polymerase chain reaction reveals over expression of genes related to immune and inflammatory responses, including T-helper type 1 related chemokines, and cytokines such as CXCR3 binding chemokines and TNFSF14. These genes may be potential interstitial cystitis biomarkers.

Preoperative physical functional status affects the long-term outcomes of elderly patients with open abdomen.

AIM: The mortality rates among elderly patients with open abdomen (OA) are high, and pre-existing comorbidities could affect the outcomes. However, long-term prognosis remains uncertain. We examined long-term outcomes in elderly patients with OA, focusing on physical functional status. METHODS: We undertook a retrospective cohort study between 2007 and 2017 at a single institution. Patients with OA who were aged ≥65 years were categorized into two groups: "good preoperative functional status" group (GFG) and "poor preoperative functional status" group (PFG). The GFG was defined as Eastern Cooperative Oncology Group/World Health Organization performance status (PS) 0-1, whereas PFG was defined as PS 2-4. The primary outcomes were survival and PS 2 years following the initial surgery. RESULTS: Of the 53 participants, 38 and 15 were assigned to the GFG and PFG, respectively. The PFG (median age, 81 years) was older than the GFG (median age, 75.5 years; P = 0.040). The 2-year survival rate was 39.5% in GFG and 6.7% in PFG, and Kaplan-Meier analysis showed significant difference (P = 0.022). Among all patients, the PS at 2 years was worse than that at discharge (P = 0.007). Preoperative PS was correlated with 2-year survival (P = 0.003), whereas age and pre-existing comorbidities were not. CONCLUSION: The long-term outcomes of elderly patients with OA are affected by the preoperative physical functional status. Functional status deteriorates in a time-dependent manner. Therefore, surgery requiring OA must be carefully considered for elderly patients with PS 2 or higher.

[Placement of a shape-memory alloy intraurethral catheter (Memokath) using transrectal ultrasonography and fluoroscopy].

Intraurethral catheters are effective in the treatment of elderly patients with benign prostate hyperplasia (BPH) who have severe complications. However, it is not easy to measure the length of the prostatic urethra and to determine an appropriate location for the urethral catheter using only fluoroscopy, especially in patient with severe mid-lobe enlargement. We attempted to place a shape-memory alloy intraurethral catheter (MEMOKATH) by transrectal ultrasonography and fluoroscopy to measure the precise length of the prostatic urethra and to determine an appropriate location for an intraurethral catheter placement. Patients were given urethral infiltration anesthesia with 2% lidocaine hydrochloride jelly and placed in the supine position. Both transrectal ultrasonography and fluoroscopy were performed to observe the bladder neck, the apex of the prostate gland, and the prostatic urethra. Transrectal ultrasonography was shown to depict them more clearly than fluoroscopy. Transrectal ultrasonography was also shown to be more suitable than fluoroscopy for measuring the prostatic urethra length, as well as for accurately positioning the MEMOKATH stent, especially in cases of BPH with mid-lobe enlargement. The MEMOKATH stent was placed in 7 patients with BPH. Urethral catheters had been put in place in 6 of these patients because of urinary retention, and large amounts of residual urine were found in the remaining patient. Three patients had severe mid-lobe enlargement. All patients were able to urinate without much residual urine after the procedure. No severe complications were noted. Transrectal ultrasonography is useful for accurately placing the MEMOKATH stent, as it provides more objective and detailed anatomical findings than fluoroscopy.

Implanted mouse bone marrow-derived cells reconstruct layered smooth muscle structures in injured urinary bladders.

This study is a preliminary investigation to determine if bone marrow-derived cells, when implanted into freeze-injured urinary bladders, differentiate into smooth muscle cells and reconstruct smooth muscle layers. Bone marrow cells were harvested from femurs of male ICR mice and cultured in collagen-coated dishes for 7 days. After 5 days of culture, the cells were transfected with green fluorescent protein (GFP) genes for identification in recipient tissues. Three days prior to implantation, the posterior urinary bladder walls of female nude mice were injured with an iron bar refrigerated by dry ice. Seven days after the culture and 3 days after the injury, adherent, proliferating GFP-labeled bone marrow-derived cells (1.0 x 10(5) cells) were implanted into the injured regions. For controls, a cell-free solution was injected. At 14 days after implantation, the experimental urinary bladders were analyzed by histological, gene expression, and cystometric investigations. Just prior to implantation, the injured regions did not have any smooth muscle layers. After 14 days, the implanted cells surviving in the recipient tissues were detected with GFP antibody. The implanted regions had distinct smooth muscle layers composed of regenerated smooth muscle marker-positive cells. The implanted GFP-labeled cells differentiated into smooth muscle cells that formed into layers. The differentiated cells contacted each other within the implanted region as well as smooth muscle cells of the host. As a result, the reconstructed smooth muscle layers were integrated into the host tissues. Control mice injected with cell-free solution developed only few smooth muscle cells and no layers. Cystometric investigations showed that mice with implanted the cells developed bladder contractions similar to normal mice, whereas control mice did not. In summary, mouse bone marrow-derived cells can reconstruct layered smooth muscle structures in injured bladders to remediate urinary dysfunction.

Bladder overactivity and hyperexcitability of bladder afferent neurons after intrathecal delivery of nerve growth factor in rats.

Nerve growth factor (NGF) has been proposed as an important mediator inducing bladder overactivity under pathological conditions such as spinal cord injury, bladder outlet obstruction, or cystitis. We therefore examined the effects of chronic NGF treatment on bladder activity and the properties of bladder afferent neurons. In adult female rats, NGF (2.5 microg/microl) was infused continuously into the intrathecal space at the L6-S1 level of spinal cord for 1 or 2 weeks using osmotic pumps (0.5 microl/h). Bladder afferent neurons were labeled with axonal transport of Fast Blue injected into the bladder wall. After intrathecal injection of NGF, cystometrograms under an awake condition showed bladder overactivity revealed by time-dependent reductions in intercontraction intervals and voided volume. ELISA analyses showed significant increases in NGF levels in L6-S1 dorsal root ganglia of NGF-treated rats. In patch-clamp recordings, dissociated bladder afferent neurons exhibiting tetrodotoxin (TTX)-resistant action potentials from NGF-treated animals were larger in diameter and had significantly lower thresholds for spike activation compared with sham rats. In addition, the number of TTX-resistant action potentials during 600 ms depolarizing pulses was significantly increased time dependently after 1 or 2 weeks of NGF application. The density of slowly inactivating A-type K+ currents was decreased by 52% in bladder afferent neurons with TTX-resistant spikes after 2 week NGF treatment. These results indicate that increased NGF levels in bladder afferent pathways and NGF-induced reduction in A-type K+ current density could contribute to the emergence of bladder overactivity as well as somal hypertrophy and hyperexcitability of bladder afferent neurons.

Natural history and etiology of high pressure voiding in male infants.

PURPOSE: We sought to determine the etiology of high pressure voiding in male infants, and to clarify the mechanisms of its improvement with maturation. MATERIALS AND METHODS: We retrospectively reviewed 106 videourodynamic studies obtained from 78 male infants with either congenital renal abnormalities or episodes of urinary tract infection, without any neurological disorders or lower urinary tract symptoms. We evaluated the relationship between age, bladder capacity and maximum voiding detrusor pressure. To evaluate voiding patterns more precisely fluoroscopic images of the lower urinary tract were continuously recorded in 64 voiding phases. RESULTS: Maximum voiding detrusor pressure showed a significant negative correlation with age as well as bladder capacity. Sharply increased detrusor pressure was noted, as were increased sphincter electromyographic activity, dilated posterior urethra and interruption of urinary stream associated with intermittent closure of the membranous urethra. Sufficient relaxation of the external sphincter was observed in all cases. True maximum voiding detrusor pressure also exhibited a significant negative correlation with age. Interruption of urine stream was commonly observed (92% of patients). Neither mean number nor duration of urine stream interruptions changed with age. The increase in detrusor pressure in response to sphincter contractions revealed a significant negative correlation with age. CONCLUSIONS: High voiding pressure in male infants results from detrusor-sphincter dyscoordination and detrusor hypercontractility in response to the dyscoordination. Its improvement with maturation is mainly due to resolution of detrusor hypercontractility.

Differences in the definition of internal target volumes using slow CT alone or in combination with thin-slice CT under breath-holding conditions during the planning of stereotactic radiotherapy for lung cancer.

PURPOSE: To investigate how the delineations of the internal target volume (ITV) made from 'slow' CT alter with reference to 'thin-slice' CT. MATERIALS AND METHODS: Thin-slice CT images taken under breath-holding conditions and slow CT images taken under shallow-breathing conditions (8s/image) of 11 lung cancers were used for this study. Five radiation oncologists delineated ITV of the 11 lesions using slow CT images (ITV1), and then redefined them with reference to thin-slice CT images (ITV2). SD-images (standard deviation image) were created for all patients from ITV images in order to visualize the regional variation of the ITVs. RESULTS: The mean value of ITV2 was smaller than that initially defined by ITV1. There was no significant change in ITV1 and ITV2 between operators with regard to standard deviation in volume. There was a significant difference in the distribution of the ratio of ITV1 to ITV2 obtained on thin-slice CTs between cases with and without ground glass opacity. In cases without ground glass opacity there was a tendency for ITV2 to have a smaller volume than ITV1. CONCLUSIONS: Combined use of slow CT and thin-slice CT in delineation of ITV contours appeared to be useful in making adjustments for obscured tumor images caused by respiratory movement.

Experimental stereotactic irradiation of normal rabbit lung: computed tomographic analysis of radiation injury and the histopathological features.

PURPOSE: The aim of this study was to establish an animal experimental model of pulmonary stereotactic irradiation and clarify the morphological patterns of pulmonary radiation injury with computed tomography and the histopathological features. MATERIALS AND METHODS: Tiny spherical regions in the lungs of seven anesthetized rabbits were irradiated stereotactically with a single fractional dose of 21-60 Gy. Subsequently, the irradiated lungs were observed biweekly with computed tomography (CT) for 24 weeks. Radiation injury of the lung was examined histopathologically in one specimen. RESULTS: Localized hypodense changes were observed 7-15 weeks after irradiation in three rabbits irradiated with 60 Gy, and the findings persisted beyond that time. The electron density ratios in the lung fields obtained from the CT images were shown to be decreasing, corresponding to the hypodensity changes. No clear increased density opacity was observed in any rabbit in the 60-Gy irradiated group. Severe localized fibrotic change was observed in the histopathological specimens. CONCLUSION: Specific localized hypodensity changes were found in only three rabbits irradiated with 60 Gy, the highest dose we employed.

Rotational and translational reproducibility of newly developed Leksell frame-based relocatable fixation system.

PURPOSE: The aim of this study was to evaluate three-dimensional movement of the cranium in a relocatable frame using positions of anatomical landmarks obtained from repeated quality-assurance (QA) computed tomography (CT) studies. MATERIALS AND METHODS: We analyzed 17 series of QA-CT data representing five patients who underwent stereotactic radiotherapy for treatment of acoustic neurinoma. Helical-CT scans with 1-mm collimation were obtained at the time of treatment planning and during the course of treatment. The right and left short processes of the incus and the top of the crista galli were used as the three anatomical reference points. RESULTS: Fluctuations in distance among the reference points were all <1 mm. The translational displacements for these points were <2 mm, with standard deviations (SD) of <2 mm. A plane that included all three reference points was defined as the reference plane. To investigate the direction of cranial rotation for each QA-CT scan, unit normal vectors of the reference plane were obtained. Three-dimensional analyses indicated that cranial rotation was greatest along the X-axis, followed by the Y-axis, with the least rotation along the Z-axis. CONCLUSION: The result suggested that movement of the craniocaudal axis in the sagittal plane was a major factor behind displacement of the cranium.

Histological and electrical properties of rat dorsal root ganglion neurons innervating the lower urinary tract.

We investigated whether primary afferent neurons innervating different regions of the lower urinary tract have different histochemical and electrophysiological properties. Neurons in rat L6-S1 DRG were identified by axonal transport of a fluorescent dye. Neurofilament-negative C-fiber cells comprise approximately 70% of bladder and proximal urethral afferent neurons that send axons through the pelvic nerves, but comprise a smaller proportion (51%) of distal urethral neurons that send axons through the pudendal nerves. Isolectin-B4 (IB4) binding was detected in a higher percentage (49%) of C-fiber neurons innervating the distal urethra than in those innervating the bladder or proximal urethra (18-22%). Neurofilament-positive A-fiber neurons innervating the distal urethra had a larger average somal size than neurons innervating the bladder or proximal urethra. In patch-clamp recordings, the majority (70%) of bladder and proximal urethral neurons were sensitive to capsaicin and exhibited TTX-resistant, high-threshold action potentials, whereas a smaller proportion (53%) of distal urethral neurons exhibited TTX-resistant spikes. T-type Ca2+ currents were observed in 47% of distal urethral neurons with TTX-sensitive spikes, but not in TTX-sensitive bladder or proximal urethral neurons. In summary, afferent neurons innervating bladder or proximal urethra differ from those innervating distal urethra. The latter, which more closely resemble cutaneous afferent neurons, consist of a smaller number of C-fiber neurons containing a higher percentage of IB4-positive cells and a more diverse population of A-fiber neurons, some of which exhibit T-type Ca2+ channels. These differences may be related to different functions of respective target organs in the lower urinary tract.

[Congenital anterior cervical fistula originating from the Wharton duct].

A 14-year-old boy presented with a spontaneous anterior cervical fistula, which exuded a saliva-like fluid during eating. Cervical examination revealed a hole 7 mm posterior to the hyoid bone, 5mm left of the median. Magnetic resonance imaging showed a low-intensity spindly mass with high-intensity margins. The mass was connected to the left submandibular gland. Contrast radiography of the fistula using Gastrografin demonstrated an ascending fistula that extended to the submandibular area. Intraoperatively, the fistula was shown to have ascended superficial to the level of the anterior cervical muscles, and it formed a cyst anterior to the hyoid bone. It then continued to the left submandibular gland. The fistula and submandibular gland were removed together. Wharton's duct was not found, and the orifice of the duct was unclear. Pathological examination of the fistula showed the lining epithelium at the side of the submandibular gland to be composed of columnar epithelial cells with stratified squamous cells at the epidermal side. Several acinar systems were found along the orifice of the fistula. There have been no previous reports of the Wharton duct running from the submandibular gland to the anterior cervical skin.

Dopaminergic mechanisms underlying bladder hyperactivity in rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the nigrostriatal pathway.

1. This study was undertaken to elucidate dopaminergic mechanisms underlying bladder hyperactivity in a rat model of Parkinson's disease (PD) induced by a unilateral 6-OHDA injection into the substantia nigra pars compacta. 2. In 6-OHDA-lesioned rats, voided volume per micturition (0.41+/-0.04 ml, mean+/-s.e.m.) measured during 24 h in a metabolic cage was significantly smaller than in sham-operated rats (0.67+/-0.07 ml). 3. Cystrometrograms (CMG) in conscious animals revealed significantly smaller bladder capacity (BC) (0.46+/-0.03 ml) in 6-OHDA-lesioned rats than in sham rats (0.72+/-0.06 ml). 4. SKF38393 (D1/D5 receptor agonist, i.v.) significantly increased BC in 6-OHDA rats without apparent effects in sham rats. SKF38393 applied intracerebroventricularly (i.c.v.) under urethane anesthesia also increased BC in 6-OHDA-lesioned rats and by a smaller increment in sham rats. 5. In contrast, quinpirole (D2/D3/D4 receptor agonist, i.v.) significantly reduced BC in sham and 6-OHDA-lesioned rats. Intrathecal injection of quinpirole similarly reduced BC in sham and 6-OHDA-lesioned rats. 6. PD128907 (D(3)-receptor agonist) did not have significant effects on BC in 6-OHDA-lesioned rats. 7. These results indicate that a rat model of PD exhibited bladder hyperactivity as observed in patients with PD, and that stimulation of D1/D5 dopamine receptors at a supraspinal site can suppress bladder hyperactivity in PD, whereas stimulation of D2/D4, but not D3, dopamine receptors had the opposite effect to reduce bladder capacity. Thus, D1/D5 dopamine receptor agonists might be effective in treating neurogenic bladder hyperactivity in PD.

Changes in spontaneous firing rate and neural synchrony in cat primary auditory cortex after localized tone-induced hearing loss.

Increase in spontaneous neural activity after noise-induced hearing loss has frequently been associated with the phenomenon of tinnitus. Eighteen juvenile and adult cats were exposed for 2 h to a 6 kHz tone with an intensity of 115 dB SPL at the cat's head. Seven non-exposed littermates and seven other normal hearing cats were used as age-matched controls. The trauma cats showed localized hearing losses, as assessed by ABR, ranging from less than 20 to 60 dB. The frequency representation in primary auditory cortex was mapped using an eight-electrode array. Single-unit spontaneous activity was recorded for 15 min. Peak cross-correlation coefficients (R) for unit cluster activity recorded on separate electrodes were calculated. We found elevated spontaneous firing rates in regions with reorganization of the tonotopic map compared to the neurons in the non-reorganized cortical regions in the same animals. A second finding was that in these regions the peak cross-correlation coefficients were also increased relative to the non-reorganized parts. A third finding was that exposed animals showed higher spontaneous activity compared to controls regardless of the presence of cortical reorganization. This may be a correlate of tinnitus in the presence of only minor hearing losses.

Changes in cat primary auditory cortex after minor-to-moderate pure-tone induced hearing loss.

In this paper we present findings in the primary auditory cortex of cats exposed for 2 h to a 115 dB SPL, 6 kHz tone at 36 days, 56 days or 118 days after birth. We evaluate the effects of age at exposure, amount of hearing loss, and time after induction of trauma on the functional reorganization of the cortical tonotopic map. We found a fairly sharp demarcation in the amount of hearing loss (20-25 dB) that caused cortical reorganization. For localized hearing losses, unmasking of excitatory contributions of neighboring frequency regions was found. For cats showing reorganization of the tonotopic map, the frequency-tuning curve bandwidth at 20 dB above threshold at CF (BW(20dB)) increased with increasing threshold at CF. Threshold at CF, and BW(20dB) increased with time after exposure. Minimum spike latency was initially increased, but subsequently decreased with time after exposure at a rate that was two times faster in cats with reorganized cortex than in cats with normal tonotopic maps, to reach the same asymptotic value. Thresholds at CF were correlated with the peripheral hearing loss at near CF frequencies as estimated from ABR measurements. The correlation between BW(20dB) and CF threshold suggests that part of the reorganization could be due to 'residual' sensitivity of the high frequency neurons to not-affected lower or higher frequencies. However, for CFs above 6 kHz, the BW(20dB) for cats with reorganization of the tonotopic map was significantly lower (on average 0.3 octave, P<0.05) than for cats with normal tonotopic maps. This is not what one would expect in cases of pseudo-plasticity characterized by concurrent shifts in BW(20dB) and CF as a result of residual sensitivity to lower frequencies.