BDNF, relative preference, and reward circuitry responses to emotional communication.

Brain derived neurotrophic factor (BDNF) regulates neural development and synaptic transmission. We have tested the hypothesis that functional variation in the BDNF gene (Val66Met polymorphism, rs6265) affects brain reward circuitry encoding human judgment and decision-making regarding relative preference. We quantified relative preference among faces with emotional expressions (angry, fearful, sad, neutral, and happy) by a keypress procedure performed offline to measure effort traded for viewing time. Keypress-based relative preferences across the ensemble of faces were mirrored significantly by fMRI signal in the orbitofrontal cortex, amygdala, and hippocampus when passively viewing these faces. For these three brain regions, there was also a statistically significant group difference by BDNF genotype in the fMRI responses to the emotional expressions. In comparison with Val/Met heterozygotes, Val/Val individuals preferentially sought exposure to positive emotions (e.g., happy faces) and had stronger regional fMRI activation to aversive stimuli (e.g., angry, fearful, and sad faces). BDNF genotype accounted for approximately 30% of the variance in fMRI signal that mirrors keypress responses to these stimuli. This study demonstrates that functional allelic variation in BDNF modulates human brain circuits processing reward/aversion information and relative preference transactions.

Design and dose distribution for rectal applicators for the high dose rate remote afterloading iridium-192 brachytherapy system.

A Remote High Dose Rate (HDR) Brachytherapy Iridium-192 System for outpatient brachytherapy procedures necessitates a variety of applicators in order to accomplish the optimal desired treatment for the patient's tumor involved anatomy. The Nucletron Corporation that manufactures the microselection HDR Iridium-192 treatment unit provided us with their standard applicators; however, a rectal applicator system was not available at the time of purchase. In order to provide this treatment to the patient, the physicians and the physicists designed a custom set of rectal applicators that would meet the current and immediate needs of our patients. A description of the clinical rationale and physical aspects of the rectal applicator system, including design and radiation dosimetry will be presented.

The natural history of benign ulcer of the rectum.

The cause of benign ulcer of the rectum is obscure, and there are varying views as to its pathogenesis. It is usually found to have a clinical onset in young adults of either sex. On sigmoidoscopy, the lesion has a characteristic appearance. The ulcers are, most often, solitary but more than one ulcer can be present. Diagnosis at biopsy is not essential, but distinctive changes can be seen in tissue from both the ulcer itself or the mucosa adjacent to the ulcer. Clinically and histologically recognizable preulcerative and nonulcerative phases are seen. Despite the benign nature of the ulcer, it may persist unchanged for many years, often associated with rectal prolapse. In general, medical and surgical methods of treatment have proved unsatisfactory.

Functional testing of braces for anterior cruciate ligament-deficient knees.

Previous studies into the efficacy of bracing anterior cruciate ligament (ACL)-deficient knees have lacked objective functional testing. In this study of function the authors compare the effectiveness of three custom-made and three off-the-shelf braces in stabilizing symptomatic, unilateral, chronic, non-reconstructed, ACL-deficient knees. Ten subjects randomly performed six functional tests with each of the six test braces. Knee function was evaluated both objectively and subjectively. Two customized functional braces (Generation II Polyaxial Knee Cage and Lenox Hill Derotation Brace) provided the most objective improvement during ACL-dependent activities and also the most subjective stability. Laterally hinged braces were as effective as the more commonly used double-hinged models. Based on this study, the authors recommend the use of laterally hinged customized functional braces in the nonoperative treatment of the symptomatic ACL-deficient knee.

A review of intra-articular knee injuries in racquet sports diagnosed by arthroscopy.

Because of the recent rapid increase in the number of knee injuries related to racquet sports, the authors undertook a retrospective study of such injuries seen over a 5-year period at the Toronto Western Hospital Sports Medicine Institute. The 121 patients who presented over the study period with a racquet-sports-related knee injury requiring arthroscopy represented 30% of all racquet-sports related injuries seen during that period. The mean age at presentation was 32.8 years and two-thirds of the patients were men. All the major racquet sports were represented. In all, 213 lesions (7 bilateral) were seen at 128 arthroscopies, and 165 arthroscopic procedures were performed. The most common lesion was meniscal followed by chondromalacia patellae, anterior cruciate ligament tears, chondral lesions and pathologic plicae. Over 90% of the patients returned to their chosen racquet sport within 3 months of the arthroscopy and most were playing at a similar performance level to that before the initial injury.

Intra-articular knee injuries in racquet sports. A review of 128 arthroscopies.

Within the last decade, there has been a significant increase in racquet sport participation. The authors report that in a 5-year period, 17% of the injuries seen in a busy sports injuries clinic were associated with racquet sports, and over half of these were injuries to the knee. The findings are reported of those patients requiring knee arthroscopy, and the patterns of injury sustained are identified. Injuries to the knee in racquet sports are largely unavoidable and are inherent to the nature of the game.