Therapeutic, III.

The findings of this study support the use of pancreatic duct stenting as an option before surgical intervention for these difficult-to-manage patients with chronic pancreatitis.

Cothron KJ, Massey JM, Onifer SM, Hubscher CH. Identification of penile inputs to the rat gracile nucleus. Am J Physiol Regul Integr Comp Physiol 294: R1015-R1023, 2008. First published January 2, 2008 doi:10.1152/ajpregu.00656.2007.-Neurons in the medullary reticular formation (MRF) of the rat receive a vast array of urogenital inputs. Using select acute and chronic spinal cord lesions to identify the location of the ascending neural circuitries providing either direct or indirect inputs to MRF from the penis, our previous studies demonstrated that the dorsal columns and dorsal half of the lateral funiculus convey low-and high-threshold inputs, respectively. In the present study, the gracile nucleus was targeted as one of the likely sources of low-threshold information from the penis to MRF. Both electrophysiological recordings and neuroanatomical tracing [injection of cholera toxin B subunit (CTB) into a dorsal nerve of the penis] were used. After discrimination of a single neuron responding to penile stimulation, testing for somatovisceral convergence was done (mechanical stimulation of the distal colon and the skin over the entire hindquarters). In 12 rats, a limited number of neurons (43 in total) responded to penile stimulation. Many of these neurons also responded to scrotal stimulation (53.5%, dorsal and/or ventral scrotum) and/or prepuce stimulation (46.5%). Histological reconstruction of the electrode tracks showed that the majority of neurons responding to penile stimulation were located ventrally within the medial onethird of the gracile nucleus surrounding obex. This location corresponded to sparse innervation by CTB-immunoreactive primary afferent terminals. These results indicate that neurons in the gracile nucleus are likely part of the pathway that provides low-threshold penile inputs to MRF, a region known to play an important role in mating processes. dorsal columns; pudendal; pelvic; convergence; cholera toxin b subunit SPINAL CORD INJURY RESULTS not only in significant sensory and motor dysfunctions of the hind limbs but in disruption of pathways responsible for normal sexual function. To devise effective treatments and therapies for these patients, a more thorough understanding of the spinal circuitries mediating sexual function is needed. In the normal spinal cord, the dorsal columns are organized with sensory information from the lower half of the body traveling more medially as it ascends in the fasciculus gracilis and from the upper body further laterally in the fasciculus cuneatus (35, 60). These somatotopically organized projections terminate into the dorsal column nuclei of the caudal medulla, which comprises the nucleus gracilis (Gr) (input from the lower body) and both the nucleus cuneatus (Cu) and external cuneate nucleus (input from the upper body). In the rat Gr, more caudal structures, such as the tail and perineum are represented medially vs. structures such as the leg and foot, which are found to be located more laterally in the nucleus (36). Maslany et al. (31) demonstrate...

ObjectiveTo assess the reliability of magnetic resonance imaging (MRI) for detection of esophageal cancer in the Levrat model of end-to-side esophagojejunostomy.BackgroundThe Levrat model has proven utility in terms of its ability to replicate Barrett’s carcinogenesis by inducing gastroduodenoesophageal reflux (GDER). Due to lack of data on the utility of non-invasive methods for detection of esophageal cancer, treatment efficacy studies have been limited, as adenocarcinoma histology has only been validated post-mortem. It would therefore be of great value if the validity and reliability of MRI could be established in this setting.MethodsChronic GDER reflux was induced in 19 male Sprague-Dawley rats using the modified Levrat model. At 40 weeks post-surgery, all animals underwent endoscopy, MRI scanning, and post-mortem histological analysis of the esophagus and anastomosis. With post-mortem histology serving as the gold standard, assessment of presence of esophageal cancer was made by five esophageal specialists and five radiologists on endoscopy and MRI, respectively.ResultsThe accuracy of MRI and endoscopic analysis to correctly identify cancer vs. no cancer was 85.3% and 50.5%, respectively. ROC curves demonstrated that MRI rating had an AUC of 0.966 (p<0.001) and endoscopy rating had an AUC of 0.534 (p = 0.804). The sensitivity and specificity of MRI for identifying cancer vs. no-cancer was 89.1% and 80% respectively, as compared to 45.5% and 57.5% for endoscopy. False positive rates of MRI and endoscopy were 20% and 42.5%, respectively.ConclusionsMRI is a more reliable diagnostic method than endoscopy in the Levrat model. The non-invasiveness of the tool and its potential to volumetrically quantify the size and number of tumors likely makes it even more useful in evaluating novel agents and their efficacy in treatment studies of esophageal cancer.

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