Incidence of peripheral neuropathy in patients with colorectal cancer receiving oxaliplatin alone vs. radiation therapy and oxaliplatin.

e18281 Background: Peripheral sensory neuropathy (PN) is a known dose limiting toxicity of oxaliplatin, used to treat patients with colorectal cancer. Patients with rectal cancer receive radiation therapy (RT) in addition to oxaliplatin in adjuvant setting. Pelvic radiation causes plexopathy due to demyelination, ischemia due to blood-vessel injury, and nerve fibrosis. To assess if RT increases the incidence of peripheral neuropathy, we conducted an analysis of patients with colorectal cancer treated with oxaliplatin alone vs. oxaliplatin and radiation. Methods: A retrospective analysis of subjects with stages II, III, and IV rectal (R) and colon (C) cancer from 2005 to 2014 was conducted. Only subjects receiving O with or without RT were included. The incidence of PN was compared for increase in subjects receiving both O and RT compared to O alone via one-sided chi-square tests at 5% alpha, both overall and after subgrouping by stage. Results: Out of 261 subjects analyzed, 158 met the study’s criteria. There were 97 C (all received only O) and 61 R (10 received only O; 51 received O+RT). PN occurred in 37% (19/51) of subjects receiving O+RT compared to 22% (24/107) receiving only O ( P= 0.025). In Stage II-III disease, PN occurred at nearly equal rates of 36% (14/39) in subjects receiving O+RT and 33% (16/46) in subjects receiving O only ( P= 0.457). However, in Stage IV disease, PN occurred in 42% (5/12) of subjects receiving O+RT compared to 13% (8/61) of subjects receiving only O ( P= 0.009). Conclusions: In our study, the incidence of PN was higher in subjects receiving both RT and O compared to O alone. Although our study did not show higher PN in stages II and III disease, patients with rectal cancer may have residual neurotoxicity from previous radiation and the subsequent exposure to oxaliplatin may be contributing to the cumulative toxicity. [Table: see text]

Accidental and experimental Closantel intoxication in Uruguayan sheep

An outbreak of Closantel intoxication in sheep in Uruguay is described. The outbreak occurred in a group of 1300 weaning lambs treated orally with a 10% solution of Closantel. One hundred forty eight lambs showed clinical signs of intoxication and 14 died. The clinical signs included mydriasis, nystagmus, and negative pupillary reflex, bilateral blindness, bump into objects, and lateral movement of the head. No macroscopic lesions were observed. The histological lesions of the retina were cytoplasmic vacuolization in ganglion cells and in cells of the inner and outer nuclear layers with different degrees of atrophy. Vacuolization and axonal degeneration were observed in the optic nerve, with multifocal areas of fibrosis and infiltration by lymphocytes and Gitter cells. To reproduce the intoxication, four sheep were given two, four and 10 times the therapeutic dose of Closantel (0.1g/kg of BW). Only the animals receiving 10 times the recommended dose showed clinical signs. The histological examination of the lesions in experimental sheep showed similar results to those described in the accidental outbreak, except for the absence of optic nerve fibrosis and inflammation, characterizing an acute phase. Axonal myelin sheaths loss, fibroblasts and collagen fibers were observed in the ultrastructural study of the optic nerve of accidental intoxicated animals. The optic nerve of experimentally intoxicated animals had vacuoles that separated the myelin sheaths of axons. To prevent outbreaks it is suggested to weigh the animals before Closantel administration to avoid errors in dose calculation.

Histologic Evaluation of Intermetatarsal Morton’s Neuroma

Background: The present study was conducted in an attempt to obtain consistent similarities among histologic findings of surgically excised neuromas. Secondly, we looked for a correlation between the presence of a neuroma with certain comorbidities. Methods: A total of 22 specimens with a preoperative diagnosis of Morton’s neuroma were sent to the pathology laboratory, and evaluation was performed by a single pathologist. Results: Degenerative changes were seen in 59% of the specimens. Patient age showed trends toward affecting nerve fibrosis, nerve diameter, vessel obstruction, and degenerative changes. The most frequent comorbidity was hypertension, seen in 44% of the participants. Conclusions: Significant histologic similarities among results were not seen; however, certain trends were discovered. Degenerative changes were appreciated in most specimens. Definite histologic findings of neuroma recur, but difficulty in consistent reproducibility may be related to factors such as age, sex, and comorbidities. (J Am Podiatr Med Assoc 103(3): 218–222, 2013)

Effect of Submuscular Versus Intramuscular Placement of Ulnar Nerve: Experimental Model in the Primate

A primate model was developed to study the effect of submuscular versus intramuscular placement upon the development of ulnar nerve fibrosis. No significant adherence was found in either location between the ulnar nerve and the flexor-pronator muscle mass. There was no significant difference in the mean nerve fibre diameter or in the percent neural tissue between the ulnar nerves in the two different locations. It is suggested that it is the interaction of the transposed ulnar nerve with other fibrous anatomical structures proximal to, across, and distal to the elbow that causes failure in ulnar nerve transposition procedures, rather than an adverse reaction between the incised flexor-pronator muscle mass and the ulnar nerve.