Lymph node status as a prognostic indicator after preoperative neoadjuvant chemoradiotherapy of rectal cancer.

AIM: The primary aim of this study was to examine lymph node status after neoadjuvant chemoradiotherapy (CRT) using a novel scoring system describing the pathological lymph node regression grade. The proposed scoring system was based on the percentage of fibrosis and the presence of residual tumour amount. The secondary aim of the study was to assess the oncological impact of this scoring system. METHOD: The project was a retrospective cohort study over a 10-year period. Two hundred and two patients with rectal cancer who had received CRT followed by curative surgery were included. A histopathologist prospectively scored each specimen and the impact of the scoring system on survival and recurrence was analysed. RESULTS: One hundred and ninety patients completed long-course preoperative CRT and formed the basis of the study. Overall, 40 recurrences (local and distant) were observed over a median follow-up of 36 months. The lymph node regression score was a significant predictor of tumour recurrence (hazard ratio 1.273, 95% CI 1.048-1.548; P = 0.015). The overall mortality rate was 21%, and a lower lymph node regression score was correlated with an improved survival curve (P = 0.01). CONCLUSION: The results demonstrate that lymph node response to neoadjuvant CRT based on a nodal regression scoring system is related to recurrence.

Impairment in a T-maze task following unilateral lateral hypothalamic lesions.

Rats with unilateral LH lesions showed great difficulty performing a contraversive turn to escape shock in a T-maze. Rats that were required to turn to the side ipsilateral to the side of their lesion did not show this performance deficit. The impairment in contraversive responding was shown to dissipate over time. It is proposed that animals with LH lesions do not suffer learning disabilities in escape-avoidance tasks, but can not activate motor behavior directed toward the side contralateral to their lesion.

Active avoidance in rats with unilateral hypothalamic and optic nerve lesions.

During the height of the contralateral sensorimotor deficit that follows unilateral hypothalamic lesions, rats demonstrate severe performance deficits when tested on a two-way active avoidance task which utilizes a visual conditioned stimulus. This deficit is observed whether or not the ipsilateral or contralateral optic nerve is sectioned in conjunction with the unilateral hypothalamic lesion. With the return of sensorimotor function contralateral to the lesion, animals that had been unable to avoid shock during their debillitated phase demonstrated significant savings when tested on the original task.

Viewing and sectioning the rat's optic nerve using cheap retractors.

A technique for sectioning the optic nerve in rats is described which permits direct viewing of the nerve during surgery. The technique results in no damage to the front of the eye. A procedure for constructing cheap, effective retractors is described.

Entrainment of the rat's activity rhythm by cyclic light following lateral geniculate nucleus lesions.

The rhythmic running-wheel activity of rats is entrained by sensory input via the visual system. The retinal projection transmitting visual information essential for entrainment of the activity rhythm is unknown. Lesions of the lateral geniculate nucleus (LGN) disrupt two projections, the primary optic tract (POT) and the superior accessory optic tract (AOT-SF). It was found that activity remained entrained to a light cycle following LGN lesions. This indicates that the POT and the AOT-SF are not necessary for entrainment. The two remaining projections, the retinohypothalamic pathway and the inferior accessory optic tract (AOT-IF), are sufficient to maintain entrainment. In light of other investigations, it is suggested that the retinohypothalamic pathway is the key projection for synchrony of the activity rhythm with environmental illumination. It was also found that LGN lesions severely impaired the subjects' ability to learn a brightness discrimination.